shell: fix compositor wakeup while locked

Compositor is locked, woken up, unlock dialog is shown; if the
compositor does to sleep again, before being unlocked, it will never
wake up again, because unlock() becomes a no-op, yet it should wake the
compositor up.

Fix this by letting unlock() to wake up the compositor, if lock surface
is present.

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

compositor/shell.c

@@ -1037,7 +1037,7 @@ unlock(struct wlsc_shell *base)
 {
 	struct wl_shell *shell = container_of(base, struct wl_shell, shell);
 
-	if (!shell->locked) {
+	if (!shell->locked || shell->lock_surface) {
 		wlsc_compositor_wake(shell->compositor);
 		return;
 	}