use String(boolean) instead of encodeURIComponent(boolean) to convert boolean to string. r=tschaub,crschmidt (closes #1982)

git-svn-id: http://svn.openlayers.org/trunk/openlayers@9035 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Format/XML.js

@@ -500,7 +500,7 @@ OpenLayers.Format.XML = OpenLayers.Class(OpenLayers.Format, {
         var value = options.value;
         if(value != null) {
             if(typeof value == "boolean") {
-                value = encodeURIComponent(value);
+                value = String(value);
             }
             node.appendChild(this.createTextNode(value));
         }