#9 Reverse ping results in check_ping

[YLearn]

Don't know if anyone cares about this but me, but it
would be nice if an option to the check_ping were to
reverse the standard return codes (i.e. OK when the
ping fails, DOWN when it does not). The reason for
this is we use dial backup for our frame network, and
sometimes the dial backup stays up after the frame
link is restored. This way someone could take action
and manually down the dial backup and avoid extra long
distance charges.