[mythtv] Database server and pings (r14205)

[Matthew Wire]

Currently if you leave the DBPort setting blank it will use the default
port of 3306.
However, your recent changes have broken this since the ping check reads
the default port as 0 and complains that it cannot access the database
(when in reality it can).

I was going to patch this but I'm not sure what the best solution is:
1. Make it mandatory that the port is specified?
2. Make a special case for default in the ping check?

Cheers,
Matthew