* origin/topic/seth/dhcp-update:
Rework to the DHCP analyzer.
First step of DHCP analyzer rearchitecture.
Add .btest scripts for dhck_ack and dhcp_discover messages verifying that new options are correctly reported in dhcp.log records.
Extend DHCP protocol analyzer with new options.
BIT-1924 #merged
Additional changes:
* Removed known-hosts.bro as the only thing populating its table was
the already-removed known-hosts-and-devices.bro. So a
known_devices.log will no longer be generated.
* In dhcp-options.pac, the process_relay_agent_inf_option had a memleak
and also process_auto_proxy_config_option looked like it accessed one
byte past the end of the available bytestring, so fixed those.
Highlights:
- Reduced all DHCP events into a single dhcp_message event. (removed legacy events since they weren't widely used anyway)
- Support many more DHCP options.
- DHCP log is completely reworked and now represents DHCP sessions
based on the transaction ID (and works on clusters).
- Removed the known-devices-and-hostnames script since it's generally
less relevant now with the updated log.
