data: Remove old bug buddy metadata from our desktop file

These keys were only used by Bug Buddy, which appears not to be used any
more. See e.g., https://bugzilla.gnome.org/show_bug.cgi?id=776796

Author: kaiw

data/meld.desktop.in

@@ -12,6 +12,3 @@ Icon=meld
 MimeType=application/x-meld-comparison;
 StartupNotify=true
 Categories=GTK;Development;
-X-GNOME-Bugzilla-Bugzilla=GNOME
-X-GNOME-Bugzilla-Product=meld
-X-GNOME-Bugzilla-Component=general