try to get trunk builds working again.

Fix missing entity error in mailcompose window

mail/components/compose/content/messengercompose.xul

@@ -31,7 +31,7 @@
 %messengercomposeDTD;
 <!ENTITY % brandDTD SYSTEM "chrome://global/locale/brand.dtd" >
 %brandDTD;
-<!ENTITY % charsetDTD SYSTEM "chrome://global/locale/charset.dtd" >
+<!ENTITY % charsetDTD SYSTEM "chrome://global/locale/charsetOverlay.dtd" >
 %charsetDTD;
 ]>