Update to upstream openvpn-2.4.2
Also:
- Switching back to OpenSSL 1.0, via compat-openssl10 and
compat-openssl10-pkcs11-helper (rhbz#1443749, rhbz#1432125, rhbz#1440468)
- Re-enable --enable-x509-alt-username which got removed during the clean-up
patches (rhbz#1443942)
- Build with lz4 library from Fedora