shell.c: Set dirty for visible views on destroyed output

The geometry for visible views will keep unchanged,
weston_view_set_position() doesn't mark these views
as dirty. So there is no chance for them to reassign output, then
these views will disappear.

Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=72946

Signed-off-by: Xiong Zhang <xiong.y.zhang@intel.com>
1 file changed