bumping to version 2.4

Change-Id: Iec9341e5db0cf0c07ce228fb5dcd9619fba9443d
diff --git a/.gitreview b/.gitreview
index 328aec6..9b45119 100644
--- a/.gitreview
+++ b/.gitreview
@@ -3,4 +3,4 @@
 port=29418
 project=onos.git
 defaultremote=origin
-defaultbranch=master
+defaultbranch=onos-2.4