NFS: Fix atime revalidation in readdir()

NFSv3 will correctly update atime on a readdir call, so there is no need to
set the NFS_INO_INVALID_ATIME flag unless the call to nfs_refresh_inode()
fails.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/proc.c b/fs/nfs/proc.c
index 845cdde..cfc4130 100644
--- a/fs/nfs/proc.c
+++ b/fs/nfs/proc.c
@@ -476,6 +476,8 @@
 	dprintk("NFS call  readdir %d\n", (unsigned int)cookie);
 	status = rpc_call_sync(NFS_CLIENT(dir), &msg, 0);
 
+	nfs_invalidate_atime(dir);
+
 	dprintk("NFS reply readdir: %d\n", status);
 	return status;
 }