NFS: fix RENAME attr in presence of directory delegations

NFS: fix RENAME attr in presence of directory delegations

Since commit 6f9bda2337f8 ("NFS: Fix directory delegation
verifier checks") xfstest generic/309 is failing because after
the rename (mv) operation, client's mtime/ctime is the same.
Update the delegated mtime when directory delegations are
present in rename.

Fixes: 6f9bda2337f8 ("NFS: Fix directory delegation verifier checks")
Signed-off-by: Olga Kornievskaia <okorniev@redhat.com>
Reviewed-by: Benjamin Coddington <bcodding@hammerspace.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>