CI: Prevent Jenkins from triggering jobs back to itself

Change-Id: I9cae8bb3d1a2cea335d3ccd88d471832549666fd

tests/CI/gates.jenkinsfile

@@ -57,6 +57,7 @@ pipeline {
 			 */
 			when {
 				not { environment name: 'GERRIT_CHANGE_NUMBER', value: '' }
+				not { environment name: 'GERRIT_EVENT_ACCOUNT_NAME', value: 'Jenkins2' }
 			}
 			steps {
 				/* Here's where we switch to scripted pipeline */

tests/CI/unittests.jenkinsfile

@@ -59,6 +59,7 @@ pipeline {
 			 */
 			when {
 				not { environment name: 'GERRIT_CHANGE_NUMBER', value: '' }
+				not { environment name: 'GERRIT_EVENT_ACCOUNT_NAME', value: 'Jenkins2' }
 			}
 			steps {
 				script {