The hook name is NetControl::acld_rule_policy and allows the
modification of acld rules before they are sent out to the network.
This allows, e.g. network policies to use nullzero instead of drop in
certain circumstances.
Netcontrol log now includes more information; before that, it had not
quite caught up to the new capabilities (like flow modifying and
redirection, as well as mac addresses).
Furthermore, this fixes a number of bugs with cluster mode (like
duplicate events), test failures due to updates in Bro, etc.
Events now generally carry the unique ID of the backend that is given
during initialization; there are a few more functions and other
bugfixes.
A few netcontrol tests are still broken (mostly due to a pcap update in
msater).
