Adding a bit of flexibility to extend and applyDefaults. First argument can now be undefined. r=pspencer,elemoine (closes #1564)

git-svn-id: http://svn.openlayers.org/trunk/openlayers@7311 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Map.js

@@ -1335,11 +1335,7 @@ OpenLayers.Map = OpenLayers.Class({
      *    false.
      */
     pan: function(dx, dy, options) {
-        // this should be pushed to applyDefaults and extend
-        if (!options) {
-            options = {};
-        }
-        OpenLayers.Util.applyDefaults(options, {
+        options = OpenLayers.Util.applyDefaults(options, {
             animate: true,
             dragging: false
         });