Make set_routerstatus_from_routerinfo() set IPv6 unspecified addresses
set_routerstatus_from_routerinfo() currently sets ipv6_orport to all zeroes. But it should be set to the unspecified IPv6 address.
This is unlikely to cause any bugs in previous Tor versions, but we should fix this for correctness.
This is a bug on commit 6d99c51 in 0.2.4.1-alpha.