Update gitreview for v2.11 so commits merge with branch=voltha-2.11 by default

Change-Id: I08cabbf708e1a10c715e76f4752ddb1404061227
diff --git a/.gitreview b/.gitreview
index bf04ac9..8551eda 100644
--- a/.gitreview
+++ b/.gitreview
@@ -3,3 +3,4 @@
 port=29418
 project=voltha-lib-go.git
 defaultremote=origin
+defaultbranch=voltha-2.11