ctrld keeps a second log file, ctrld-journal.log, next to ctrld.log. The
journal holds all warnings and errors and each event with the field
journal=true. It stays on disk after a start of the service and after a
self-upgrade. Each log file starts with a Log header line. Each log send
upload starts with the same line, made at send time, and has a limit of
about 16 MB.
