Unused variable from nn_xbus_data removed

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>
diff --git a/src/protocols/bus/xbus.c b/src/protocols/bus/xbus.c
index 7f0d9fb..0a16571 100644
--- a/src/protocols/bus/xbus.c
+++ b/src/protocols/bus/xbus.c
@@ -81,7 +81,6 @@
     data = nn_alloc (sizeof (struct nn_xbus_data),
         "pipe data (xbus)");
     alloc_assert (data);
-    data->pipe = pipe;
     nn_fq_add (&xbus->inpipes, pipe, &data->initem, 8);
     nn_dist_add (&xbus->outpipes, pipe, &data->outitem);
     nn_pipe_setdata (pipe, data);
diff --git a/src/protocols/bus/xbus.h b/src/protocols/bus/xbus.h
index 0cc2193..f5a2e7e 100644
--- a/src/protocols/bus/xbus.h
+++ b/src/protocols/bus/xbus.h
@@ -33,7 +33,6 @@
 struct nn_sockbase *nn_xbus_create (int fd);
 
 struct nn_xbus_data {
-    struct nn_pipe *pipe;
     struct nn_dist_data outitem;
     struct nn_fq_data initem;
 };