2 - The HSDir flag given by authorities now requires the Stable flag. For
3 the current network, this results in going from 2887 to 2806 HSDirs.
4 Also, it makes it harder for an attacker to launch a sybil attack by
5 raising the effort for a relay to become Stable which takes at the
6 very least 7 days to do so and by keeping the 96 hours uptime
7 requirement for HSDir. Implements ticket #8243.