Do not run taskCleanup if running hive in sequential mode

hive_no_system_exit.patch

           if (tsk.ifRetryCmdWhenFail()) {
-            if (running.size() != 0) {
+            if (running.size() != 0 && executeTasksInParallel()) {
               taskCleanup();
             }
             // in case we decided to run everything in local mode, restore the
@@ -1183,7 +1183,7 @@ public class Driver implements CommandProcessor {
             }
             SQLState = "08S01";
             console.printError(errorMessage);
-            if (running.size() != 0) {
+            if (running.size() != 0 && executeTasksInParallel()) {
               taskCleanup();
             }
             // in case we decided to run everything in local mode, restore the
@@ -1299,6 +1299,10 @@ public class Driver implements CommandProcessor {
     return (0);
   }

+  private boolean executeTasksInParallel() {
+    return HiveConf.getBoolVar(conf, HiveConf.ConfVars.EXECPARALLEL);
+  }
+