Merge branch 'jl/pack-transfer-avoid-double-close'

The codepath that send_pack() calls pack_objects() mistakenly
closed the same file descriptor twice, leading to potentially
closing a wrong file descriptor that was opened in the meantime.

* jl/pack-transfer-avoid-double-close:
  Clear fd after closing to avoid double-close error

fetch-pack.c

@@ -747,6 +747,10 @@ static int get_pack(struct fetch_pack_args *args,
 		close(cmd.out);
 	}
 
+	if (!use_sideband)
+		/* Closed by start_command() */
+		xd[0] = -1;
+
 	ret = finish_command(&cmd);
 	if (!ret || (args->check_self_contained_and_connected && ret == 1))
 		args->self_contained_and_connected =