Fix dead stores found by scan-build

In addition to removing unused code, two minor problems are fixed:
 (1) `resize set` and `resize adjust` did not error when given
too many arguments.
 (2) `orientation` was incorrectly overridden to be 'U' for
scroll events in the swaybar tray `handle_click` function.

client/pool-buffer.c

@@ -85,7 +85,6 @@ static struct pool_buffer *create_buffer(struct wl_shm *shm,
 	close(fd);
 	unlink(name);
 	free(name);
-	fd = -1;
 
 	buf->size = size;
 	buf->width = width;