scoutfs-utils: return error for small device

The check for a small device didn't return an error code because it was
copied from error tests of ret for an error code.  It has to generate
one, do so.

Signed-off-by: Zach Brown <zab@versity.com>

utils/src/mkfs.c

@@ -178,6 +178,7 @@ static int write_new_fs(char *path, int fd, u8 quorum_count)
 	if (size < limit) {
 		fprintf(stderr, "%llu byte device too small for min %llu byte fs\n",
 			size, limit);
+		ret = -EINVAL;
 		goto out;
 	}