libbpf: Close fd in bpf_object__reuse_map

pin_fd is dup-ed and assigned in bpf_map__reuse_fd. Close it
in bpf_object__reuse_map after reuse.

Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220319030533.3132250-1-hengqi.chen@gmail.com

Author: chenhengqi

tools/lib/bpf/libbpf.c

@@ -4823,8 +4823,8 @@ bpf_object__reuse_map(struct bpf_map *map)
 	}
 
 	err = bpf_map__reuse_fd(map, pin_fd);
+	close(pin_fd);
 	if (err) {
-		close(pin_fd);
 		return err;
 	}
 	map->pinned = true;