boks-ping improvements

[fjtc]

Implement the improvements suggested by Tim Jelinsky:

1. baseport is only listening on master. Only needed by replicas and maybe client during install or preregistered host. Often, firewall rules will prevent this from anything but replicas.
2. baseport_+ 1 is needed on replicas, but often large customers turn off listening on this port for the master.
3. baseport +2 is needed only on replicas and is only used FROM master. This can alos include replicas when they may be used in failover as master.
4. baseport +3 is only FROM the master. No other systems ever needs this. This can include replicas when they may be used in failover as master.
5. In 7.1, we have made addition to showmaster command. Check out showmaster -Avs:

BoKS # showmaster -Avs
replica71 192.168.56.181 (0.663 msec, 0.000 msec)
master71 192.168.56.180 (1001.090 msec, 0.000 msec)