clients: Fix a couple of warnings

clients/dnd.c

@@ -247,9 +247,7 @@ data_source_target(void *data,
 	struct dnd *dnd = dnd_drag->dnd;
 	cairo_surface_t *surface;
 	struct wl_buffer *buffer;
-	struct wl_data_device *device;
 
-	device = input_get_data_device(dnd_drag->input);
 	dnd_drag->mime_type = mime_type;
 	if (mime_type)
 		surface = dnd_drag->opaque;

clients/tablet-shell.c

@@ -192,17 +192,6 @@ lockscreen_draw(struct tablet_shell *shell)
 	window_flush(shell->lockscreen);
 }
 
-static void
-lockscreen_button_handler(struct widget *widget,
-			  struct input *input, uint32_t time,
-			  int button, int state, void *data)
-{
-	struct tablet_shell *shell = data;
-
-	window_destroy(shell->lockscreen);
-	shell->lockscreen = NULL;
-}
-
 static void
 show_lockscreen(void *data, struct tablet_shell *tablet_shell)
 {