fs/cifs: fix parsing of dfs referrals

fs/cifs: fix parsing of dfs referrals

The problem was that the first referral was parsed more than once
and so the caller tried the same referrals multiple times.

The problem was introduced partly by commit
066ce6899484d9026acd6ba3a8dbbedb33d7ae1b,
where 'ref += le16_to_cpu(ref->Size);' got lost,
but that was also wrong...

Cc: <stable@vger.kernel.org>
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Tested-by: Björn Jacke <bj@sernet.de>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>