Remove the style commands command set, because we ain't got not style. Fixes JS errors/exceptions.

editor/ui/composer/content/TextEditorAppShell.xul

@@ -58,7 +58,6 @@
     <commandset id="composerMenuItems"/>
     <commandset id="composerEditMenuItems"/>
     <commandset id="composerSaveMenuItems"/>    
-    <commandset id="composerStyleMenuItems"/>
   </commands>
 
   <broadcaster id="args" value="chrome://editor/content/EditorInitPagePlain.html"/>