fix(): correctly access minErr

ngMinErr is not available in the build, but it is available
during unit tests. The added tests don't actually catch this error,
they have just been added for completeness.

src/ngAnimate/shared.js

@@ -72,6 +72,7 @@ var isPromiseLike = function(p) {
   return p && p.then ? true : false;
 };
 
+var ngMinErr = angular.$$minErr('ng');
 function assertArg(arg, name, reason) {
   if (!arg) {
     throw ngMinErr('areq', "Argument '{0}' is {1}", (name || '?'), (reason || "required"));

test/ngAnimate/animateSpec.js

@@ -1408,7 +1408,24 @@ describe("animations", function() {
       });
     }));
 
-    it('should allow an element to pinned elsewhere and still be available in animations',
+    it('should complain if the arguments are not elements',
+      inject(function($animate, $compile, $document, $rootScope, $rootElement) {
+
+      var element = jqLite('<div></div>');
+
+      expect(function() {
+        $animate.pin(element);
+      }).toThrow();
+
+      expect(function() {
+        $animate.pin(null, $rootElement);
+      }).toThrow();
+
+      dealoc(element);
+    }));
+
+
+    it('should allow an element to be pinned elsewhere and still be available in animations',
       inject(function($animate, $compile, $document, $rootElement, $rootScope) {
 
       var innerParent = jqLite('<div></div>');