fix(autocomplete): always hide the progressbar when clearing the input

src/components/autocomplete/js/autocompleteController.js

@@ -775,6 +775,7 @@ function MdAutocompleteCtrl ($scope, $element, $mdUtil, $mdConstant, $mdTheming,
     if (!$scope.noCache && cache[ term ]) {
       ctrl.matches = cache[ term ];
       updateMessages();
+      setLoading(false);
     } else {
       fetchResults(searchText);
     }