Since we no longer need to support SSLv2-style cipher lists, start
unravelling the maze of function pointers and callbacks by directly
calling ssl3_{get,put}_cipher_by_char() and removing the
ssl_{get,put}_cipher_by_char macros.

Prompted by similar changes in boringssl.

ok guenther.
Remove disabled (weakened export and non-ephemeral DH) cipher suites from
the cipher list. This reduces code size, saves data segment space and
prevents them from being turned back on at runtime by flipping a bit in
memory.

ok guenther@