Disable the problematic gtk usage for use with pygtkcompat. The following
commit removes these tools/UIs entirely but we may as well leave this
piece in the history in case anyone does want a starting point for reusing
them.
(Bitbake rev: c53c7418d392452450352ca2175667dbdbd92401)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>