Kea incorrectly handles options with trailing null.

Customer discovered incorrect handling of option (specifically hostname) that cause issues if followed by an RFC-breaking null. It has been discovered (thanks @tmark ) that there was a specific "hack" put in place in ISC DHCP to deal with this exact issue. Unfortunately, broken options are rarely under the control of the operator running the DHCP server...

Anyway, the report (And Thomas' response) can be found in the original customer ticket: https://support.isc.org/Ticket/Display.html?id=14338

This may cause some issues with customer hooks:

processing this option may also break [customer's] IP tracking hook- [The hook] was unable to find lease time (51) because the packet printing is being truncated. Nothing after the host name is being printed.

There is a work-around, but I'll be opening another issue shortly to explain a change that I feel necessary on that as well.

Workaround:

    "hostname-char-set": "[^A-Za-z0-9.-]",
    "hostname-char-replacement": ""

placed in the dhcp-ddns stanza.