Add notification about Start gating job.

https://mirantis.jira.com/browse/PROD-28062

Change-Id: I77ca23d27015845e5b89fef22f695d99ae939a2e
diff --git a/gating-pipeline.groovy b/gating-pipeline.groovy
index 7cbdfa0..3313d48 100644
--- a/gating-pipeline.groovy
+++ b/gating-pipeline.groovy
@@ -43,6 +43,8 @@
             def skipProjectsVerify = ['mk/docker-jnlp-slave']
 
             stage("test") {
+                //notification about Start job
+                ssh.agentSh(String.format("ssh -p %s %s@%s gerrit review %s,%s -m \"'Build Started %s'\"", defGerritPort, GERRIT_NAME, GERRIT_HOST, GERRIT_CHANGE_NUMBER, GERRIT_PATCHSET_NUMBER, BUILD_URL))
                 //check Code-Review
                 if (!gerrit.patchsetHasApproval(gerritChange.currentPatchSet, "Code-Review", "+")) {
                     throw new Exception('Change don\'t have a CodeReview+1, reject gate')