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

Change-Id: I325cb37631359ac284729adb70970010d6ab2e6b
diff --git a/.gitreview b/.gitreview
index 0d979d3..40c7a88 100644
--- a/.gitreview
+++ b/.gitreview
@@ -3,3 +3,4 @@
 port=29418
 project=mac-learning.git
 defaultremote=origin
+defaultbranch=voltha-2.11