bumping to version 2.3

Change-Id: If08c3382ec3b46ce0d93b96721356f95891cd660
diff --git a/.gitreview b/.gitreview
index 328aec6..e9b5a9b 100644
--- a/.gitreview
+++ b/.gitreview
@@ -3,4 +3,4 @@
 port=29418
 project=onos.git
 defaultremote=origin
-defaultbranch=master
+defaultbranch=onos-2.3