Restore ability to build with V2_HANDSHAKE_SERVER

Fixes bug 4677; bugfix on 0.2.3.2-alpha. Fix by "piet".
Restore prop198 behavior from 4677 patch

The previous commit from piet would have backed out some of proposal
198 and made servers built without the V2 handshake not use the
unrestricted cipher list from prop198.

Bug not in any released Tor.
Merge branch 'bug4677'