nfsd: do_probe_callback should not clear rpc stats

Now that cb_stats are static (since commit
ff7d9756b501744540be65e172d27ee321d86103)
there's no need to clear them.

Initially I thought it might make sense to do
that every callback probing but since the stats
are per-program and they are shared between possibly
several client callback instances, zeroing them out
seems like the wrong thing to do.

Note that that commit also introduced a bug
since stats.program is also being cleared in the process
and it is not restored after the memset as it used to be.

Signed-off-by: Benny Halevy <[e-mail]>
Signed-off-by: J. Bruce Fields <[e-mail]>

fs/nfsd/nfs4callback.c

···
 	addr.sin_port = htons(cb->cb_port);
 	addr.sin_addr.s_addr = htonl(cb->cb_addr);
 
-	/* Initialize rpc_stat */
-	memset(args.program->stats, 0, sizeof(struct rpc_stat));
-
 	/* Create RPC client */
 	client = rpc_create(&args);
 	if (IS_ERR(client)) {