UI freeze breakage (maybe): sync empty trash alerts in nautilus and trashapplet

[Luca Ferretti <elle uca libero it>]

A really long long title for a really short short body: see bug #165241
[1]

Well, OK, some more words. Relevant changes:
- Different primary/secondary labels (this is just a string enhancement,
so IMHO it's not an UI breakage)
- Use WARNING instead QUESTION as per HIG
- Use GtkMessaDialog instead GtkDialog+(a-lot-of-widgets)
- remove the GTK_STOCK_DELETE from confirmation button 'cause it's yet
used in Nautilus for the move-to-trash action

Please see this[2] thread on nautilus ml too. Thanks.

[1] http://bugzilla.gnome.org/show_bug.cgi?id=165241
[2] http://mail.gnome.org/archives/nautilus-list/2005-
January/msg00119.html
-- 
Luca Ferretti <elle uca libero it>