Currently, ssl3_put_char_by_bytes(NULL, NULL) is just a long handed way

Currently, ssl3_put_char_by_bytes(NULL, NULL) is just a long handed way
of writing "2". Add a define for the SSL3_CIPHER_VALUE_SIZE (rather than
using a less-readable hardcoded constant everywhere) and replace the
ssl3_put_char_by_bytes(NULL, NULL) calls with it.

ok bcook@ miod@