Comment 7 for bug 1756791

Reviewed: https://review.opencontrail.org/40790
Committed: http://github.com/Juniper/contrail-controller/commit/5f6cb940282018a3682c29a5e8ac4c9355e8f0af
Submitter: Zuul (<email address hidden>)
Branch: R4.0

commit 5f6cb940282018a3682c29a5e8ac4c9355e8f0af
Author: Ananth Suryanarayana <email address hidden>
Date: Sun Mar 18 22:07:48 2018 -0700

During contrail-control shutdown, disable node_info timer before its deletion

During contrail-control shutdown process, node_info_log_timer is directly
deleted from main thread. This can process to crash if the timer happens to
be running or scheduled to fire at exactly the same time (from other threads).

Fix by first disabling the timer and then wait till the timer gets fully
cancelled before proceeding ahead with the deletion of the timer.

Found and verified the fix using bgp_stress_test

Change-Id: Ia9909164d7f41074b6a38f48d332a0cc7b040ea1
Closes-Bug: 1756791