Comment 4 for bug 1431297

Control node backtrace is as follows. Same as bug 1430091.

#0 0x00007f1277f19bb9 in raise () from /lib/x86_64-linux-gnu/libc.so.6
#1 0x00007f1277f1cfc8 in abort () from /lib/x86_64-linux-gnu/libc.so.6
#2 0x00007f1277f12a76 in ?? () from /lib/x86_64-linux-gnu/libc.so.6
#3 0x00007f1277f12b22 in __assert_fail () from /lib/x86_64-linux-gnu/libc.so.6
#4 0x000000000045a996 in IFMapExporter::StateUpdateOnDequeue (this=0x16a8d90, update=update@entry=0x7f11e8bdd2f0, dequeue_set=...,
    is_delete=<optimized out>) at controller/src/ifmap/ifmap_exporter.cc:548
#5 0x0000000000489002 in IFMapUpdateSender::ProcessUpdate (this=this@entry=0x16aa090, update=update@entry=0x7f11e8bdd2f0, base_send_set=...)
    at controller/src/ifmap/ifmap_update_sender.cc:225
#6 0x0000000000489544 in IFMapUpdateSender::Send (this=0x16aa090, imarker=<optimized out>) at controller/src/ifmap/ifmap_update_sender.cc:184
#7 0x0000000000489c4b in IFMapUpdateSender::SendTask::Run (this=0x7f121db16fe0) at controller/src/ifmap/ifmap_update_sender.cc:41
#8 0x0000000000a5e930 in TaskImpl::execute (this=0x7f12716df940) at controller/src/base/task.cc:243