gerritPipeline: do not reset labels when the build starts.

Trivial rebase do not reset the Verified/Code-Style labels
on changes. Gerrit CI should therefore respect the existing labels
and not reset anything when a build starts.

This allows changes to be merged immediately after a trivial
rebase, without having to wait for another verification build.

Issue: Issue 12721
Change-Id: I75a4964812ff2de0d0046c62dd455088eafaffb3
diff --git a/vars/gerritPipeline.groovy b/vars/gerritPipeline.groovy
index c3c166e..d3ac30a 100644
--- a/vars/gerritPipeline.groovy
+++ b/vars/gerritPipeline.groovy
@@ -27,7 +27,6 @@
 
         if (hasChangeNumber()) {
             stage('Preparing'){
-                gerritReview labels: ['Verified': 0, 'Code-Style': 0]
                 collectBuildModes()
             }
         }