vfs_ceph_new: avoid setting errno in cephmount_cache_update

vfs_ceph_new: avoid setting errno in cephmount_cache_update

Do not set 'errno' to ENOENT in cephmount_cache_update. Setting this
errno value upon newly inserted entry may cause vfs_ceph_connect to
change errno to non-zero value even though the final result is OK.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15703

Signed-off-by: Shachar Sharon <ssharon@redhat.com>
Reviewed-by: Anoop C S <anoopcs@samba.org>
Reviewed-by: John Mulligan <jmulligan@redhat.com>
(cherry picked from commit 1f7581c9edb32a2a63bf032f7e167be8a401c3d5)