This avoids complexity where failing to read the config file in gitosis-run-hook is non-fatal, but only on the first run. gitosis-init will take care of config file reading and just pass a RawConfigParser instance to run_hook.post_update.
Hide internal gitosis-ssh and gitosis-gitweb, it's all in gitosis-run-hook.
Sadly, no unit tests on this level, for now.