ui-snapshot.c: change mime-type for tar.gz and tar.bz2

The updated mime-types seems to work better than the old ones with both
safari and firefox.

Signed-off-by: Lars Hjemli <hjemli@gmail.com>

ui-snapshot.c

@@ -58,8 +58,8 @@ static int write_tar_bzip2_archive(struct archiver_args *args)
 
 const struct cgit_snapshot_format cgit_snapshot_formats[] = {
 	{ ".zip", "application/x-zip", write_zip_archive, 0x1 },
-	{ ".tar.gz", "application/x-tar", write_tar_gzip_archive, 0x2 },
-	{ ".tar.bz2", "application/x-tar", write_tar_bzip2_archive, 0x4 },
+	{ ".tar.gz", "application/x-gzip", write_tar_gzip_archive, 0x2 },
+	{ ".tar.bz2", "application/x-bzip2", write_tar_bzip2_archive, 0x4 },
 	{ ".tar", "application/x-tar", write_tar_archive, 0x8 },
 	{}
 };