Upgrade ONOS to use 2.3.0-b2 version of the yang tools

Change-Id: I1111958d4d172320a00d595c20ff82a385a4be3e
diff --git a/tools/dev/bin/patch-yang-libs b/tools/dev/bin/patch-yang-libs
index 0522d9e..f04f488 100755
--- a/tools/dev/bin/patch-yang-libs
+++ b/tools/dev/bin/patch-yang-libs
@@ -3,7 +3,7 @@
 # Patches lib/BUCK file to use locally built YANG tools.
 # -----------------------------------------------------------------------------
 
-BVER=2.2.0
+BVER=2.3.0-b2
 SVER=2.3-SNAPSHOT
 
 YANG_TOOLS_ROOT=${YANG_TOOLS_ROOT:-~/onos-yang-tools}