libinput: Fix the close_restricted interface callback

libinput: Fix the close_restricted interface callback

libinput is supposed to take a close callback in its interface
to allow you to call out to a privileged API to close FDs. But
the FD that libinput passes you is bogus, because
libinput_remove_source closes the FD on which it's passed. This
is really bad, as the libinput_source really doesn't own the FD
which it's passed, so it shouldn't be trying to close() it.

Only one out of the four users of libinput_remove_source actually
wants their FD closed, so move the close() call there.

Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>