libweston-desktop/xdg-shell: Check surface size against acknowledged size

We were checking against the pending size, which lead some clients
(simple-egl) to crash because they sent a buffer before acknowledging
the latest configure event.

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>
Tested-by: Emmanuel Gil Peyrot <emmanuel.peyrot@collabora.com>
Reviewed-by: Jonas Ã…dahl <jadahl@gmail.com>
2 files changed