Remove retries in changes validation

When validating incoming changes, fail the build at
the first failure so that flaky changes won't get a positive
verified label.

Change-Id: I769ac564d796f8bdd61cae4f48f19ea75e541bfa
diff --git a/jenkins/gerrit-verifier-change.groovy b/jenkins/gerrit-verifier-change.groovy
index 3096162..b8fab36 100644
--- a/jenkins/gerrit-verifier-change.groovy
+++ b/jenkins/gerrit-verifier-change.groovy
@@ -387,7 +387,7 @@
   def builds = []
   println "Running validation jobs using $tools builds for $modes ..."
   modes.collect {
-    prepareBuildsForMode(refspec,sha1,changeUrl,it,tools,branch,3,Globals.codeStyleBranches.contains(branch))
+    prepareBuildsForMode(refspec,sha1,changeUrl,it,tools,branch,1,Globals.codeStyleBranches.contains(branch))
   }.each { builds += it }
 
   def buildsWithResults = getResultsOfBuildsInParallel(builds)