move the about dialog menu item to the right place on OSX by giving it a special id attribute.

Thanks to Don Crandall for the fix!

mail/components/addrbook/content/addressbook.xul

@@ -365,7 +365,7 @@
             <menuitem accesskey="&releaseCmd.accesskey;" label="&releaseCmd.label;" oncommand="loadThrobberUrl('mailnews.release_notes.url');"/>
             <menuitem accesskey="&hintsAndTips.accesskey;" label="&hintsAndTips.label;" oncommand="loadThrobberUrl('mailnews.hints_and_tips.url');"/>
             <menuseparator/>
-            <menuitem accesskey="&aboutCmd.accesskey;"
+            <menuitem id="aboutName" accesskey="&aboutCmd.accesskey;"
                       label="&aboutCmd.label;"
                       oncommand="window.openDialog('chrome://messenger/content/aboutDialog.xul', 'About', 'modal,centerscreen,chrome,resizable=no');"/>
           </menupopup>

mail/components/compose/content/messengercompose.xul

@@ -431,7 +431,7 @@
           <menuitem accesskey="&releaseCmd.accesskey;" label="&releaseCmd.label;" oncommand="loadThrobberUrl('mailnews.release_notes.url');"/>
           <menuitem accesskey="&hintsAndTips.accesskey;" label="&hintsAndTips.label;" oncommand="loadThrobberUrl('mailnews.hints_and_tips.url');"/>
           <menuseparator/>
-          <menuitem accesskey="&aboutCmd.accesskey;"
+          <menuitem id="aboutName" accesskey="&aboutCmd.accesskey;"
                     label="&aboutCmd.label;"
                     oncommand="window.openDialog('chrome://messenger/content/aboutDialog.xul', 'About', 'modal,centerscreen,chrome,resizable=no');"/>
         </menupopup>