retry mechanism for radius client 1.1.6

[Frank Cusack]

> Looking at the retry handling in rc_send_server() in sendserver.c, it
> appears that "retries" actually means "tries".
...

Indeed.

> I think the fix is simply to change the line to:
>
>   if (retries++ >= retry_max)

Unfortunately many many systems are deployed with the previous semantics,
so I think it'd be better to simply document the behavior.  Alternatively,
a new keyword to implement the new semantics, with a log warning about
the old keyword being deprecated.

-frank