It looks like for the most part this is no longer used. Hoewver, I see
at least two exceptions. The first is the function log_file_name() in
util.cc, which appears to now only be used by DebugLogger.cc. The second
is open_log_file() in base/init-bare.bro (which calls log_file_name()),
which only appears to be called by policy/misc/profiling.bro.
(I've held off on filing a ticket on this until I understand the
view of what's expected.)