Bumping ONOS to point to ONOS YANG Tools 2.2.0-b2

Change-Id: I23b2ed67ed0fb5ef4ec0731a37dcd8b058102298
diff --git a/tools/build/onos-buck b/tools/build/onos-buck
index 4481673..1fbd567 100755
--- a/tools/build/onos-buck
+++ b/tools/build/onos-buck
@@ -5,8 +5,8 @@
 
 set -e
 
-BUCK_URL="http://onlab.vicci.org/onos/third-party/buck-v2017.07.18.02.zip"
-BUCK_SHA="147ca3ec72af966f9be5eaaa409fca76377ba718"
+BUCK_URL="http://onlab.vicci.org/onos/third-party/buck-v2017.07.28.01.zip"
+BUCK_SHA="a35a44ed10ba756fe7f6b6f13386a9fa5e515b86"
 
 [  "-U" = "$1" ] && shift && FORCE_UPDATE=True