libweston: Use weston_signal_emit_mutable for all destroy signals
A left over from our switch to weston_signal_emit_mutable().
Signed-off-by: Marius Vlad marius.vlad@collabora.com
A left over from our switch to weston_signal_emit_mutable().
Signed-off-by: Marius Vlad marius.vlad@collabora.com