repack: retain the return value of pack-objects

During the review process of the previous commit (repack: rewrite the
shell script in C), Johannes Sixt proposed to retain any exit codes from
the sub-process, which makes it probably more obvious in case of failure.

As the commit before should behave as close to the original shell
script, the proposed change is put in this extra commit.
The infrastructure however was already setup in the previous commit.
(Having a local 'ret' variable)

Signed-off-by: Stefan Beller <stefanbeller@googlemail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/repack.c

@@ -231,7 +231,7 @@ int cmd_repack(int argc, const char **argv, const char *prefix)
 
 	ret = start_command(&cmd);
 	if (ret)
-		return 1;
+		return ret;
 
 	nr_packs = 0;
 	out = xfdopen(cmd.out, "r");
@@ -244,7 +244,7 @@ int cmd_repack(int argc, const char **argv, const char *prefix)
 	fclose(out);
 	ret = finish_command(&cmd);
 	if (ret)
-		return 1;
+		return ret;
 	argv_array_clear(&cmd_args);
 
 	if (!nr_packs && !quiet)