update jenkins-trigger file to pass down info about target branch (#3264)

* Update jenkins-trigger.groovy

* Update jenkins-trigger.groovy

* Update jenkins-trigger.groovy

* Update jenkins-trigger.groovy

* Update jenkins-trigger.groovy

.ci/jenkins/jenkins-trigger.groovy

@@ -24,6 +24,7 @@
 // Parameters which ngraph-unittest uses:
 String  PR_URL = CHANGE_URL
 String  PR_COMMIT_AUTHOR = CHANGE_AUTHOR
+String  PR_TARGET = CHANGE_TARGET
 String  JENKINS_BRANCH = "master"
 Integer TIMEOUTTIME = "3600"
 // BRANCH parameter is no loner needed
@@ -56,7 +57,7 @@ timestamps {
         
         echo "Calling ngraph-ci-premerge.groovy"
         def ngraphCIPreMerge = load("${JENKINS_DIR}/ngraph-ci-premerge.groovy")
-        ngraphCIPreMerge(PR_URL, PR_COMMIT_AUTHOR, JENKINS_BRANCH, TIMEOUTTIME)
+        ngraphCIPreMerge(PR_URL, PR_COMMIT_AUTHOR, JENKINS_BRANCH, TIMEOUTTIME, PR_TARGET)
         echo "ngraph-ci-premerge.groovy completed"
 
     }  // End:  node