Remove a call to SSL_set_state from s_server

s_server was (ab)using SSL_set_state to force a renegotiation. This is a
bad way to do things and does not work with the new state machine code, so
we need to do it a different way.

Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>