Update pulling code from gerrit

 - With the update to gerrit, the script was not pulling the changeset,
   so the checks were running on master

Change-Id: I8061b73b5a9ab7adff1472a1760ffd4ae7b0d857
diff --git a/jjb/OnosSystemTest/check-style.sh b/jjb/OnosSystemTest/check-style.sh
index 2559978..88e0a8b 100644
--- a/jjb/OnosSystemTest/check-style.sh
+++ b/jjb/OnosSystemTest/check-style.sh
@@ -3,8 +3,8 @@
 cd $WORKSPACE
 rm -rf OnosSystemTest
 rm -f pep8Result.txt
-git clone https://gerrit.onosproject.org/OnosSystemTest; cd OnosSystemTest
-git review -d ${GERRIT_CHANGE_NUMBER}
+git clone https://gerrit.onosproject.org/OnosSystemTest && cd OnosSystemTest
+git fetch "https://gerrit.onosproject.org/OnosSystemTest" $GERRIT_REFSPEC && git checkout FETCH_HEAD
 
 cd
 cd $WORKSPACE/OnosSystemTest/