libmultipath: fix error return in snprint_devices()

If an error occurs, snprint_devices() should return a negative
error code, not 1.

Fixes: d041258 ("libmultipath: snprint_devices(): use udev_enumerate")

Suggested-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Martin Wilck <mwilck@suse.com>
(cherry picked from commit 5c59d5d)

Author: bmarzins

libmultipath/print.c

@@ -1989,7 +1989,7 @@ int snprint_devices(struct config *conf, struct strbuf *buff,
 
 	enm = udev_enumerate_new(udev);
 	if (!enm)
-		return 1;
+		return errno ? -errno : -1;
 	if ((r = udev_enumerate_add_match_subsystem(enm, "block")) < 0)
 		goto out;