SUNRPC: Add a (empty for the moment) destructor for rpc_wait_queues

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index c5c0175..06f064d 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -170,6 +170,8 @@
 	BUG_ON(!RB_EMPTY_ROOT(&clp->cl_state_owners));
 	if (__test_and_clear_bit(NFS_CS_IDMAP, &clp->cl_res_state))
 		nfs_idmap_delete(clp);
+
+	rpc_destroy_wait_queue(&clp->cl_rpcwaitq);
 #endif
 }