Moving to 2.3.1-SNAPSHOT

Change-Id: I20efdcdb7b2e4b691668f83c91fca7a0218ade4d
diff --git a/.gitreview b/.gitreview
index c44e0f2..b22df6e 100644
--- a/.gitreview
+++ b/.gitreview
@@ -3,3 +3,4 @@
 port=29418
 project=kafka-onos.git
 defaultremote=origin
+defaultbranch=kafka-onos-2.3