zdtm unix_sock: don't use errno

In this place, errno is not being set and can be 0 or some random value,
so we should not use it. In case errno happens to be 0, we end up returning
a success status from a function while we should have returned a failure.
Signed-off-by: Kir Kolyshkin <kir@openvz.org>
Acked-by: Andrew Vagin <avagin@gmail.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

test/zdtm/live/streaming/unix_sock.c

@@ -110,9 +110,8 @@ static int setup_clnt_sock(void)
 	int ret = 0;
 
 	if (fill_sock_name(&name, filename) < 0) {
-		ret = -errno;
 		pr_perror("filename \"%s\" is too long", filename);
-		return ret;
+		return -1;
 	}
 
 	sock = socket(PF_LOCAL, SOCK_STREAM, 0);