NFS: Fix nfs_verify_change_attribute()

We don't care about whether or not some other process on our client is
changing the directory while we're in nfs_lookup_revalidate(), because the
dcache will take care of ensuring local atomicity.
We can therefore remove the test for nfs_caches_unstable().

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 07df192..e275a6e 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -646,7 +646,7 @@
 {
 	if (IS_ROOT(dentry))
 		return 1;
-	if (dentry->d_time == NFS_I(dir)->cache_change_attribute)
+	if (nfs_verify_change_attribute(dir, dentry->d_time))
 		return 1;
 	return 0;
 }