Child ticket of legacy/trac#15801. In `directory_permits_begindir_requests()`, a relay doesn't accept `BEGIN_DIR` cell if the DirPort isn't set. ``` int directory_permits_begindir_requests(const or_options_t *options) { return options->BridgeRelay != 0 || options->DirPort_set; } ``` Fixing this would make every relay being able to answer directory requests without a DirPort. Turns out, it's a part of proposal 237 so we should make those two happens and incidently helping with the global issue in the parent ticket.