Tolerate disappearance of named bug-workaround bits,

without invalidating user configurations.  Just set the bit's value
to zero.  Set a more precise version test for CVE-2005-2969 (i.e.
SSL_OP_MSIE_SSLV2_RSA_PADDING) which was later re-cycled as
SSL_OP_SAFARI_ECDHE_ECDSA_BUG.  Always ignore the latter, it is not
relevant with SMTP.