compositor: do not release if re-attaching buffer
compositor: do not release if re-attaching buffer

If a client called wl_surface.attach with the same wl_buffer as
previously, the compositor would mistakenly send a release on that
buffer. This will cause problems only when clients start to properly use
the wl_buffer.release event.

Do not send wl_buffer.release if the same buffer is attached again.

Signed-off-by: Pekka Paalanen <6c0263d81461c956d504307112a4ce25eaacc3d1@gmail.com>

Fantu/compositor-spice,kwm81/weston,jonnylamb/weston,mchalupa/weston,xorgy/weston,Fantu/compositor-spice,eyolfson/weston,jonnylamb/weston,udoprog/weston,sir-murray/weston,sir-murray/weston,krezovic/weston,krezovic/weston,eyolfson/weston,giucam/weston,Fantu/compositor-spice,Tarnyko/weston-xdg_surface_present,Gnurou/weston,kwm81/weston,udoprog/weston,giucam/weston,Tarnyko/weston-xdg_surface_present,xorgy/weston,Gnurou/weston,mchalupa/weston