compositor: only authorized client can bind desktop_shell

Check, that only the desktop-shell client spawned by the compositor
(desktop-shell plugin) is allowed to bind to desktop_shell interface.
Other clients will receive an error like:

  wl_display@1.error(desktop_shell@20, 0,
  "permission to bind desktop_shell denied")

The error has the proper object id and interface type.

Note: desktop-shell cannot be started manually anymore, it has to be
started by the compositor automatically.

Signed-off-by: Pekka Paalanen <ppaalanen@gmail.com>
1 file changed