chore($$raf) remove moz prefix for requestAnimationFrame

This drops support for Firefox 22 and older.

The moz-prefix is still supported, but there is an effort to drop it eventually:
https://bugzilla.mozilla.org/show_bug.cgi?id=909154

Closes angular#9577

Author: realityking

src/ng/raf.js

@@ -3,12 +3,10 @@
 function $$RAFProvider() { //rAF
   this.$get = ['$window', '$timeout', function($window, $timeout) {
     var requestAnimationFrame = $window.requestAnimationFrame ||
-                                $window.webkitRequestAnimationFrame ||
-                                $window.mozRequestAnimationFrame;
+                                $window.webkitRequestAnimationFrame;
 
     var cancelAnimationFrame = $window.cancelAnimationFrame ||
                                $window.webkitCancelAnimationFrame ||
-                               $window.mozCancelAnimationFrame ||
                                $window.webkitCancelRequestAnimationFrame;
 
     var rafSupported = !!requestAnimationFrame;