Improve DNS Leak test

[Stalinium 44]

IPLeak only shows the DNS server IP of the AirVPN server I'm connected to. Mullvad's leak tester on the other hand shows my ISP's DNS server in addition to that. Some other testers detect the ISP too.
The DNS Leak test should be more rigorous in how it does the test to not give a false sense of security.

Software: default OpenVPN GUI on Windows, OpenVPN 2.5.1

[Clodo 176]

Thanks for the feedback, the issue is under investigation.

[wscddns2 0]

I think y hace a same problem look like a MITM