Update gitreview for v2.11 to use branhc voltha-2.11 as default

Change-Id: I814559ac108041e73b2424c04199a67e300963cf
diff --git a/.gitreview b/.gitreview
index 473a40c..2dcac27 100644
--- a/.gitreview
+++ b/.gitreview
@@ -3,4 +3,4 @@
 port=29418
 project=voltha-onos.git
 defaultremote=origin
-defaultbranch=master
+defaultbranch=voltha-2.11