VOL-3492 panic in rw-core.
error log, in case of agent.start() failure, uses nil reference of childDevice.

Change-Id: Ib6ab65b7a0ad6e8356f16f2977d72e0daf080816
(cherry picked from commit 23bd8c72e526400f25cfc6ebf1c13945c186ff90)
diff --git a/.gitreview b/.gitreview
index c70a26b..50460e5 100644
--- a/.gitreview
+++ b/.gitreview
@@ -3,3 +3,4 @@
 port=29418
 project=voltha-go.git
 defaultremote=origin
+defaultbranch=voltha-2.5