MINOR: log: handle extra log origins in _process_send_log_override()

MINOR: log: handle extra log origins in _process_send_log_override()

Thanks to the previous commit, it is now possible to register additional
log origins that may be used from log-profile section as 'on' steps.

As such, let's make _process_send_log_override() function aware of them
by trying to lookup in the tree of extra logging steps in the default
switch-case catchall. If the log origin id matches with the id of the
extra logging step, we use the associated log format instead of the
"any" log format.