T5634: Smoketest add encryption ciphers

As providers legacy default option was deleted with
insecure DES and Blowfish ciphers, the smoketest cannot pass
without adding encyption ciphers

Otherwise

Oct 16 09:41:34 r4 openvpn-vtun5[9648]: DCO version: N/A
Oct 16 09:41:34 r4 openvpn-vtun5[9648]: Cipher BF-CBC not supported
Oct 16 09:41:34 r4 openvpn-vtun5[9648]: Exiting due to fatal error

Fix the smoketest