Fix error code in nfs_lookup_verify_inode()

Fix error code in nfs_lookup_verify_inode()

Return -ESTALE to force a lookup when the file has no more links

Signed-off-by: Lance Shelton <lance.shelton@hammerspace.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Orabug: 28789030

(cherry picked from commit a61246c96195fc5f7500f6842e883b9eb1567d8d)
Signed-off-by: Calum Mackay <calum.mackay@oracle.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Tested-by: alfredo.ramirez@oracle.com
Signed-off-by: Brian Maly <brian.maly@oracle.com>