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

Change-Id: I7ac91885fac6df2c4ecf3d8c07400cd3874def6b
diff --git a/.gitreview b/.gitreview
index 981cc4c..9533f68 100644
--- a/.gitreview
+++ b/.gitreview
@@ -3,3 +3,4 @@
 port=29418
 project=olt.git
 defaultremote=origin
+defaultbranch=voltha-2.11