remove unnecessary variable

Author: wware

docs/content/guide/dev_guide.mvc.understanding_controller.ngdoc

@@ -309,7 +309,7 @@ and the test is straight forward
 describe('myController function', function() {
 
     describe('myController', function() {
-        var scope, ctrl;
+        var scope;
 
         beforeEach(inject(function($rootScope, $controller) {
             scope = $rootScope.$new();