fix($compile):remove controllerAs requirement

src/ng/compile.js

@@ -1029,17 +1029,11 @@ function $CompileProvider($provide, $$sanitizeUriProvider) {
     }
     if (isObject(bindings.bindToController)) {
       var controller = directive.controller;
-      var controllerAs = directive.controllerAs;
       if (!controller) {
         // There is no controller, there may or may not be a controllerAs property
         throw $compileMinErr('noctrl',
               'Cannot bind to controller without directive \'{0}\'s controller.',
               directiveName);
-      } else if (!identifierForController(controller, controllerAs)) {
-        // There is a controller, but no identifier or controllerAs property
-        throw $compileMinErr('noident',
-              'Cannot bind to controller without identifier for directive \'{0}\'.',
-              directiveName);
       }
     }
     return bindings;