bumping to version 2.1

Change-Id: I032501b26ecbd14147d02594f867c28740fde134
diff --git a/.gitreview b/.gitreview
index 328aec6..fbe8ddc 100644
--- a/.gitreview
+++ b/.gitreview
@@ -3,4 +3,4 @@
 port=29418
 project=onos.git
 defaultremote=origin
-defaultbranch=master
+defaultbranch=onos-2.1