fix(tabs): make deprecated controller work with 1.3.x

Closes #4583

Author: Foxandxss

src/tabs/tabs.js

@@ -301,9 +301,9 @@ angular.module('ui.bootstrap.tabs')
       $log.warn('TabsetController is now deprecated. Use UibTabsetController instead.');
     }
 
-    return $controller('UibTabsetController', {
+    angular.extend(this, $controller('UibTabsetController', {
       $scope: $scope
-    });
+    }));
   }])
 
   .directive('tabset', ['$log', '$tabsSuppressWarning', function($log, $tabsSuppressWarning) {