AMBARI-8674. Disable pre-upgrade checks until API is ready. (yusaku)

ambari-web/app/config.js

@@ -57,6 +57,7 @@ App.isManagedMySQLForHiveEnabled = false;
 App.enableExperimental = false;
 
 App.supports = {
+  preUpgradeCheck: false,
   stackUpgrade: false,
   autoRollbackHA: false,
   alwaysEnableManagedMySQLForHive: false,

ambari-web/app/controllers/main/admin/stack_and_upgrade_controller.js

@@ -282,12 +282,16 @@ App.MainAdminStackAndUpgradeController = Em.Controller.extend(App.LocalStorage,
    * @param version
    */
   runPreUpgradeCheck: function(version) {
-    App.ajax.send({
-      name: "admin.rolling_upgrade.pre_upgrade_check",
-      sender: this,
-      data: version,
-      success: "runPreUpgradeCheckSuccess"
-    })
+    if (App.supports.preUpgradeCheck) {
+      App.ajax.send({
+        name: "admin.rolling_upgrade.pre_upgrade_check",
+        sender: this,
+        data: version,
+        success: "runPreUpgradeCheckSuccess"
+      });
+    } else {
+      this.upgrade(version);
+    }
   },
 
   /**