desktop-shell: Use the grabbed pointer in popup_grab_button

This should be identical to the pointer in shset->seat.

A later patch prevents direct access to seat->pointer, using the
known valid pointer in the grab will be nicer than using the
getter functions that patch introduces.

Reviewed-by: Jonas Ã…dahl <jadahl@gmail.com>
Signed-off-by: Derek Foreman <derekf@osg.samsung.com>
1 file changed