patchTeach fsck and prune that tmp_obj_ file names may not be 14 bytes long

> As Shawn pointed out, not all temporary file creation routines can
> ensure that the generated temporary file is of a certain length.
> e.g. Java's createTempFile(prefix, suffix). So just depend on the
> prefix 'tmp_obj_' for detection.
> 
> Update prune, and fix the "fix" introduced by a08c53a1 :)

> Signed-off-by: Brandon "appendixless" Casey <casey@nrlssc.navy.mil>
> ---
>  builtin-fsck.c  |    2 +-
>  builtin-prune.c |    9 ++++-----
>  2 files changed, 5 insertions(+), 6 deletions(-)
> 
> diff --git a/builtin-fsck.c b/builtin-fsck.c
> index 6eb7da8..d3f3de9 100644
> --- a/builtin-fsck.c
> +++ b/builtin-fsck.c
> @@ -385,7 +385,7 @@ static void fsck_dir(int i, char *path)
>  			add_sha1_list(sha1, DIRENT_SORT_HINT(de));
>  			continue;
>  		}
> -		if (prefixcmp(de->d_name, "tmp_obj_"))
> +		if (!prefixcmp(de->d_name, "tmp_obj_"))
>  			continue;
>  		fprintf(stderr, "bad sha1 file: %s/%s\n", path, de->d_name);
>  	}
> diff --git a/builtin-prune.c b/builtin-prune.c
> index 947de8c..c767a0a 100644
> --- a/builtin-prune.c
> +++ b/builtin-prune.c
> @@ -69,11 +69,6 @@ static int prune_dir(int i, char *path)
>  			if (de->d_name[0] != '.')
>  				break;
>  			continue;
> -		case 14:
> -			if (prefixcmp(de->d_name, "tmp_obj_"))
> -				break;
> -			prune_tmp_object(path, de->d_name);
> -			continue;
>  		case 38:
>  			sprintf(name, "%02x", i);
>  			memcpy(name+2, de->d_name, len+1);
> @@ -90,6 +85,10 @@ static int prune_dir(int i, char *path)
>  			prune_object(path, de->d_name, sha1);
>  			continue;
>  		}
> +		if (!prefixcmp(de->d_name, "tmp_obj_")) {
> +			prune_tmp_object(path, de->d_name);
> +			continue;
> +		}
>  		fprintf(stderr, "bad sha1 file: %s/%s\n", path, de->d_name);
>  	}
>  	if (!show_only)
> -- 
> 1.5.6.2
>