If the client uses a v2 cipherlist on the renegotiation handshake,
it looks as if they could fail to get a good cert chain from the
server, since they server would re-disable certificate chaining.

This patch makes it so the code that make the server side of the
first v2 handshake special can get called only once.

Fix for 4591; bugfix on 0.2.0.20-rc.