fix(uiSelectCtrl): Prevent error when using ngAnimate < v1.4

Fixes #1619 
Closes #1626

Author: fafnirical

src/uiSelectController.js

@@ -125,7 +125,7 @@ uis.controller('uiSelectCtrl',
 
       var container = $element.querySelectorAll('.ui-select-choices-content');
       var searchInput = $element.querySelectorAll('.ui-select-search');
-      if (ctrl.$animate && ctrl.$animate.enabled(container[0])) {
+      if (ctrl.$animate && ctrl.$animate.on && ctrl.$animate.enabled(container[0])) {
         var animateHandler = function(elem, phase) {
           if (phase === 'start' && ctrl.items.length === 0) {
             // Only focus input after the animation has finished