NFSv4.1: Add DESTROY_CLIENTID

Ensure that we destroy our lease on last unmount

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index a50bdfb..7d10875 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -209,6 +209,7 @@
 	if (nfs4_has_session(clp)) {
 		nfs4_deviceid_purge_client(clp);
 		nfs4_destroy_session(clp->cl_session);
+		nfs4_destroy_clientid(clp);
 	}
 
 }