NFSd: call rpc_destroy_wait_queue() from free_client()

Mainly to ensure that we don't leave any hanging timers.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 230d21c..32b699b 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1107,6 +1107,7 @@
 		WARN_ON_ONCE(atomic_read(&ses->se_ref));
 		free_session(ses);
 	}
+	rpc_destroy_wait_queue(&clp->cl_cb_waitq);
 	free_svc_cred(&clp->cl_cred);
 	kfree(clp->cl_name.data);
 	idr_destroy(&clp->cl_stateids);