Fix or condition in gerrit-verifier-flow.groovy

The usage of 'or' instead of 'OR' causes the query to not
find changes on stable-3.0.

Change-Id: I472f29a1c91249f75169505883c390c4e4652cb5
diff --git a/jenkins/gerrit-verifier-flow.groovy b/jenkins/gerrit-verifier-flow.groovy
index 7eda79c..b561a57 100644
--- a/jenkins/gerrit-verifier-flow.groovy
+++ b/jenkins/gerrit-verifier-flow.groovy
@@ -51,7 +51,7 @@
 println ""
 println "Querying Gerrit for last modified changes since ${since} ..."
 
-def gerritQuery = "status:open project:gerrit (branch:stable-2.14 OR branch:stable-2.15 OR branch:stable-2.16 or branch:stable-3.0 OR branch:master) since:\"" + since + "\""
+def gerritQuery = "status:open project:gerrit (branch:stable-2.14 OR branch:stable-2.15 OR branch:stable-2.16 OR branch:stable-3.0 OR branch:master) since:\"" + since + "\""
 
 queryUrl = new URL(Globals.gerrit + "changes/?pp=0&o=CURRENT_REVISION&o=DETAILED_ACCOUNTS&o=DETAILED_LABELS&n=" + Globals.maxChanges + "&q=" +
                       gerritQuery.encodeURL())