spice-display: fix qemu_spice_cursor_refresh_bh locking

spice-display: fix qemu_spice_cursor_refresh_bh locking

spice-display should not call the ui/console.c functions dpy_cursor_define
and dpy_moues_set with the SimpleSpiceDisplay lock taken.  That will cause
a deadlock, because the DisplayChangeListener callbacks will take the lock
again.  It is also in general a bad idea to invoke generic callbacks with a
lock taken, because it can cause AB-BA deadlocks in the long run.  The only
thing that requires care is that the cursor may disappear as soon as the
mutex is released, so you need an extra cursor_get/cursor_put pair.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-id: 20180720063109.4631-3-pbonzini@redhat.com

[ kraxel: fix dpy_cursor_define() call ]

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>