Revert "NFS: nfs_rename() handle -ERESTARTSYS dentry left behind"

This reverts commit 920b4530 which could
call d_move() without holding the directory's i_mutex, and reverts commit
d4ea7e3c "NFS: Fix old dentry rehash after
move", which was a follow-up fix.

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Fixes: 920b4530 ("NFS: nfs_rename() handle -ERESTARTSYS dentry left behind")
Cc: stable@vger.kernel.org # v4.10+
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>