YARN-7940. Fixed a bug in ServiceAM ZooKeeper initialization.

           (Contributed by Billie Rinaldi)

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/impl/zk/CuratorService.java

@@ -288,6 +288,9 @@ public class CuratorService extends CompositeService
       registrySecurity.applySecurityEnvironment(builder);
       //log them
       securityConnectionDiagnostics = buildSecurityDiagnostics();
+      if (LOG.isDebugEnabled()) {
+        LOG.debug(securityConnectionDiagnostics);
+      }
       framework = builder.build();
       framework.start();
     }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/impl/zk/RegistrySecurity.java

@@ -762,6 +762,8 @@ public class RegistrySecurity extends AbstractService {
           LOG.info(
               "Enabling ZK sasl client: jaasClientEntry = " + jaasClientEntry
                   + ", principal = " + principal + ", keytab = " + keytab);
+          break;
+
         default:
           clearZKSaslClientProperties();
           break;