Bug 106053, remove unused XHTML namespace declarations, and fix incorrect namespace usages. r=harishd, sr=hewitt.

suite/debugQA/content/debugQATextEditorShell.xul

@@ -38,7 +38,7 @@
 <!DOCTYPE window SYSTEM "chrome://editor/locale/editor.dtd"> 
 
 <!-- NOTE: If we don't have "title" set, text editor doesn't work! -->
-<window id="main-window" xmlns:html="http://www.w3.org/1999/xhtml"
+<window id="main-window"
         xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"
         onload="TextEditorOnLoad()"
         onunload="EditorShutdown()"