Disable polygerrit check definition for master branch

We disable running verifications of frontend only change on GerritForge
CI on master branch and relies on LUCI verification.

Change-Id: Ib2937cec95d3b6b85cbfd5d3b689f579b41e7cc0
diff --git a/jenkins/checker_definitions.txt b/jenkins/checker_definitions.txt
index 617f819..6b4c77e 100644
--- a/jenkins/checker_definitions.txt
+++ b/jenkins/checker_definitions.txt
@@ -27,7 +27,7 @@
     "name": "PolyGerrit UI Tests",
     "description": "Executes unit/integration tests for PolyGerrit UI",
     "repository": "gerrit",
-    "query": "(dir:polygerrit-ui OR file:WORKSPACE) AND (branch:stable-3.5 OR branch:stable-3.6 OR branch:stable-3.7 OR branch:stable-3.8 OR branch:master)",
+    "query": "(dir:polygerrit-ui OR file:WORKSPACE) AND (branch:stable-3.5 OR branch:stable-3.6 OR branch:stable-3.7 OR branch:stable-3.8)",
     "blocking": []
   }