Make Go to next unread message work for thunderbird when crossing folders. We were missing a declaration for MSG_FOLDER_FLAG_JUNK

which triggered a JS error.

mail/base/content/commandglue.js

@@ -39,6 +39,7 @@ var MSG_FOLDER_FLAG_DRAFTS = 0x0400;
 var MSG_FOLDER_FLAG_QUEUE = 0x0800;
 var MSG_FOLDER_FLAG_INBOX = 0x1000;
 var MSG_FOLDER_FLAG_TEMPLATES = 0x400000;
+var MSG_FOLDER_FLAG_JUNK = 0x40000000;
 
 function OpenURL(url)
 {