MFC: The import of openssl to address the FreeBSD-SA-15:10.openssl security

MFC: The import of openssl to address the FreeBSD-SA-15:10.openssl security
     advisory includes a change which rejects handshakes with DH parameters
     below 768 bits.  sendmail releases prior to 8.15.2 (not yet released),
     defaulted to a 512 bit DH parameter setting for client connections.
     This commit chages that default to 1024 bits.  sendmail 8.15.2, when
     released well use a default of 2048 bits.

git-svn-id: svn://svn.freebsd.org/base/stable/10@284485 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f