nfs: standardize the rename response container

Right now, v3 and v4 have their own variants. Create a standard struct
that will work for v3 and v4. v2 doesn't get anything but a simple error
and so isn't affected by this.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 3aa13c1..a3c21cc 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2577,7 +2577,7 @@
 		.new_name = new_name,
 		.bitmask = server->attr_bitmask,
 	};
-	struct nfs4_rename_res res = {
+	struct nfs_renameres res = {
 		.server = server,
 	};
 	struct rpc_message msg = {