object-file: fix leak on conversion failure

I'm not sure exactly how to trigger the leak, but it seems fairly
obvious that the `content' buffer should be freed even if
convert_object_file() fails.  Noticed while working in this area
on unrelated things.

Signed-off-by: Eric Wong <e@80x24.org>
Acked-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: Eric Wong

object-file.c

@@ -1711,9 +1711,9 @@ static int oid_object_info_convert(struct repository *r,
 			ret = convert_object_file(&outbuf,
 						  the_hash_algo, input_algo,
 						  content, size, type, !do_die);
+			free(content);
 			if (ret == -1)
 				return -1;
-			free(content);
 			size = outbuf.len;
 			content = strbuf_detach(&outbuf, NULL);
 		}