Fix xmlToDom in Gecko 2.

--HG--
branch : testing

common/content/util.js

@@ -708,7 +708,7 @@ const Util = Module("util", {
         }
         switch (node.nodeKind()) {
         case "text":
-            return doc.createTextNode(node);
+            return doc.createTextNode(String(node));
         case "element":
             let domnode = doc.createElementNS(node.namespace(), node.localName());
             for each (let attr in node.@*)