Bug #289448 --> delete the old en-US-mail.jar file when installing a new

build

r=bsmedberg

mail/installer/windows/mail.jst

@@ -681,6 +681,7 @@ function upgradeCleanup()
   deleteThisFile("Components", "nsBackgroundUpdateService.js");
 
   deleteThisFile("Chrome",  "chrome.rdf");
+  deleteThisFile("Chrome",  "en-US-mail.jar");
 
   deleteThisFile("Program",     "defaults/pref/all.js");
   deleteThisFile("Program",     "defaults/pref/security-prefs.js");