GridRenderContainer.js registerViewportAdjuster patch

- renamed wrongly named 'registerViewportAdjuster' fn to 'removeViewportAdjuster'
- when checking if a function is in the viewportAdjusters array need to check that its index is > -1

Author: Alex

src/js/core/factories/GridRenderContainer.js

@@ -174,10 +174,10 @@ angular.module('ui.grid')
    * @description Removes an adjuster, should be used when your element is destroyed
    * @param {function} func the adjuster function we want to remove
    */
-  GridRenderContainer.prototype.removeViewportAdjuster = function registerViewportAdjuster(func) {
+  GridRenderContainer.prototype.removeViewportAdjuster = function removeViewportAdjuster(func) {
     var idx = this.viewportAdjusters.indexOf(func);
 
-    if (typeof(idx) !== 'undefined' && idx !== undefined) {
+    if (idx > -1) {
       this.viewportAdjusters.splice(idx, 1);
     }
   };