Explicitly set ONOS_ROOT

Change-Id: I4a90c404e4a678d46f0b1e68a753c05a87be404f
diff --git a/jjb/onos/onos-verify.yaml b/jjb/onos/onos-verify.yaml
index c95a2ec..c97e018 100644
--- a/jjb/onos/onos-verify.yaml
+++ b/jjb/onos/onos-verify.yaml
@@ -93,6 +93,7 @@
     #put shell scripts in file then make sure shell check is installed on verify vms
       - shell: |
             #!/bin/bash
+            ONOS_ROOT=`pwd`
             . tools/build/envDefaults
             echo $PATH
             onos-buck build onos