missing .gtkbuilder file on bug-buddy

["Fernando Herrera" <fherrera onirica com>]

Hi,

I just added bug-buddy.gtkbuilder file to bug-buddy's POTFILES.in. It
doesn't include any new string not present on the old glade file, so
all of them should have a translation.

Just to inform and to check that this is ok. If not I can revert the
change and ask for a proper string freeze break.

Thanks!

Salu2