Patch to fix destroy() being called on an undefined object

heron-mc/heron-mc#399

Author: dracic

lib/OpenLayers/Map.js

@@ -816,7 +816,9 @@ OpenLayers.Map = OpenLayers.Class({
 
         if (this.controls != null) {
             for (var i = this.controls.length - 1; i>=0; --i) {
-                this.controls[i].destroy();
+                if(this.controls[i] != undefined) {
+                    this.controls[i].destroy();
+                }
             } 
             this.controls = null;
         }