MAX_SKDC_TIMEOUT misleading

[Frank Cusack]

This value is set to 30 by default, however the code which uses it
(sendto_kdc.c) does an exponential backoff:

    for (timeout = krb5_skdc_timeout_1; timeout < krb5_max_skdc_timeout;
         timeout <<= krb5_skdc_timeout_shift) {

The actual max value is 16s.  Setting it to 30 is misleading.  I'd say
change this to 16, but an alternative is 32.

thx
/fc