NPE when deactivating org.onosproject.netcfglinksprovider

steps to recreate the issue
1.app deactivate org.onosproject.openflow
2.app activate org.onosproject.openflow-base org.onosproject.hostprovider org.onosproject.netcfglinksprovider
3.app deactivate org.onosproject.netcfglinksprovider
4.app activate org.onosproject.netcfglinksprovider

org.onosproject.provider.netcfglinks.NetworkConfigLinksProvider$InternalPacketProcessor@32577f0b threw an exception
java.lang.NullPointerException
at org.onosproject.provider.netcfglinks.NetworkConfigLinksProvider$InternalPacketProcessor.process(NetworkConfigLinksProvider.java:348)[160:org.onosproject.onos-providers-netcfglinks:1.10.0.SNAPSHOT]
at org.onosproject.net.packet.impl.PacketManager$InternalPacketProviderService.processPacket(PacketManager.java:379)[127:org.onosproject.onos-core-net:1.10.0.SNAPSHOT]
at org.onosproject.provider.of.packet.impl.OpenFlowPacketProvider$InternalPacketProvider.handlePacket(OpenFlowPacketProvider.java:171)[168:org.onosproject.onos-providers-openflow-packet:1.10.0.SNAPSHOT]
at org.onosproject.openflow.controller.impl.OpenFlowControllerImpl.processPacket(OpenFlowControllerImpl.java:316)[166:org.onosproject.onos-protocols-openflow-ctl:1.10.0.SNAPSHOT]
at org.onosproject.openflow.controller.impl.OpenFlowControllerImpl$OpenFlowSwitchAgent.processMessage(OpenFlowControllerImpl.java:727)[166:org.onosproject.onos-protocols-openflow-ctl:1.10.0.SNAPSHOT]
at org.onosproject.openflow.controller.driver.AbstractOpenFlowSwitch.handleMessage(AbstractOpenFlowSwitch.java:267)[163:org.onosproject.onos-protocols-openflow-api:1.10.0.SNAPSHOT]
at org.onosproject.openflow.controller.impl.OFChannelHandler.dispatchMessage(OFChannelHandler.java:1293)[166:org.onosproject.onos-protocols-openflow-ctl:1.10.0.SNAPSHOT]
at org.onosproject.openflow.controller.impl.OFChannelHandler.access$2100(OFChannelHandler.java:83)[166:org.onosproject.onos-protocols-openflow-ctl:1.10.0.SNAPSHOT]
at org.onosproject.openflow.controller.impl.OFChannelHandler$ChannelState$9.processOFPacketIn(OFChannelHandler.java:732)[166:org.onosproject.onos-protocols-openflow-ctl:1.10.0.SNAPSHOT]
at org.onosproject.openflow.controller.impl.OFChannelHandler$ChannelState.processOFMessage(OFChannelHandler.java:985)[166:org.onosproject.onos-protocols-openflow-ctl:1.10.0.SNAPSHOT]
at org.onosproject.openflow.controller.impl.OFChannelHandler.messageReceived(OFChannelHandler.java:1274)[166:org.onosproject.onos-protocols-openflow-ctl:1.10.0.SNAPSHOT]
at org.jboss.netty.channel.SimpleChannelHandler.handleUpstream(SimpleChannelHandler.java:88)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.handler.timeout.IdleStateAwareChannelHandler.handleUpstream(IdleStateAwareChannelHandler.java:36)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.channel.DefaultChannelPipeline$DefaultChannelHandlerContext.sendUpstream(DefaultChannelPipeline.java:791)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.channel.SimpleChannelUpstreamHandler.messageReceived(SimpleChannelUpstreamHandler.java:124)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(SimpleChannelUpstreamHandler.java:70)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.channel.DefaultChannelPipeline$DefaultChannelHandlerContext.sendUpstream(DefaultChannelPipeline.java:791)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.handler.timeout.ReadTimeoutHandler.messageReceived(ReadTimeoutHandler.java:184)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(SimpleChannelUpstreamHandler.java:70)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.channel.DefaultChannelPipeline$DefaultChannelHandlerContext.sendUpstream(DefaultChannelPipeline.java:791)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.handler.timeout.IdleStateHandler.messageReceived(IdleStateHandler.java:294)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(SimpleChannelUpstreamHandler.java:70)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.channel.DefaultChannelPipeline$DefaultChannelHandlerContext.sendUpstream(DefaultChannelPipeline.java:791)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:296)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.handler.codec.frame.FrameDecoder.unfoldAndFireMessageReceived(FrameDecoder.java:462)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.handler.codec.frame.FrameDecoder.callDecode(FrameDecoder.java:443)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.handler.codec.frame.FrameDecoder.messageReceived(FrameDecoder.java:303)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(SimpleChannelUpstreamHandler.java:70)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:559)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:268)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.channel.Channels.fireMessageReceived(Channels.java:255)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.channel.socket.nio.NioWorker.read(NioWorker.java:88)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.channel.socket.nio.AbstractNioWorker.process(AbstractNioWorker.java:108)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.channel.socket.nio.AbstractNioSelector.run(AbstractNioSelector.java:337)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.channel.socket.nio.AbstractNioWorker.run(AbstractNioWorker.java:89)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.channel.socket.nio.NioWorker.run(NioWorker.java:178)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.util.ThreadRenamingRunnable.run(ThreadRenamingRunnable.java:108)[95:org.jboss.netty:3.10.5.Final]
at org.jboss.netty.util.internal.DeadLockProofWorker$1.run(DeadLockProofWorker.java:42)[95:org.jboss.netty:3.10.5.Final]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)[:1.8.0_77]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)[:1.8.0_77]
at java.lang.Thread.run(Thread.java:745)[:1.8.0_77]