Fix "Migrate instance to another host" popup modal (#2803)

* Fix "Migrate instance to another host" popup

* fix OK button that was not working as it should have been

Author: rafaelweingartner

ui/scripts/ui-custom/migrate.js

@@ -100,6 +100,7 @@
 
                             $('div.overlay').fadeOut(function() {
                                 $('div.overlay').remove();
+                                $(':ui-dialog').dialog('destroy');
                             });
                         }
                         else {
@@ -121,7 +122,8 @@
                         });
                     }
                 }]
-            }).parent('.ui-dialog').overlay();
+            });
+            cloudStack.applyDefaultZindexAndOverlayOnJqueryDialogAndRemoveCloseButton($dataList);
         };
     };
 }(cloudStack, jQuery));