Properly destroy OpenLayers.Handler.MouseWheel, patch from fredj. Added

tests for it as well. (Closes #935)


git-svn-id: http://svn.openlayers.org/trunk/openlayers@4100 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Handler/MouseWheel.js

@@ -46,9 +46,8 @@ OpenLayers.Handler.MouseWheel = OpenLayers.Class(OpenLayers.Handler, {
      * Method: destroy
      */    
     destroy: function() {
-        this.deactivate();
-        this.wheelListener = null;
         OpenLayers.Handler.prototype.destroy.apply(this, arguments);
+        this.wheelListener = null;
     },
 
     /**