Merge remote-tracking branch 'origin/topic/seth/dhcp-update'

* 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.

testing/btest/scripts/base/protocols/dhcp/dhcp-ack-msg-types.btest

@@ -0,0 +1,6 @@
+# This tests that DHCP leases are logged in dhcp.log
+# The trace has a message of each DHCP message type,
+# but only one lease should show up in the logs.
+
+# @TEST-EXEC: bro -r $TRACES/dhcp/dhcp_ack_subscriber_id_and_agent_remote_id.trace %INPUT
+# @TEST-EXEC: btest-diff dhcp.log

testing/btest/scripts/base/protocols/dhcp/dhcp-discover-msg-types.btest

@@ -0,0 +1,6 @@
+# This tests that DHCP leases are logged in dhcp.log
+# The trace has a message of each DHCP message type,
+# but only one lease should show up in the logs.
+
+# @TEST-EXEC: bro -r $TRACES/dhcp/dhcp_discover_param_req_and_client_id.trace %INPUT
+# @TEST-EXEC: btest-diff dhcp.log

testing/btest/scripts/base/protocols/dhcp/dhcp-sub-opts.btest

@@ -0,0 +1,2 @@
+# @TEST-EXEC: bro -r $TRACES/dhcp/dhcp_ack_subscriber_id_and_agent_remote_id.trace %INPUT protocols/dhcp/sub-opts
+# @TEST-EXEC: btest-diff dhcp.log