Fix false positives of openvpn process detection

[mrtnmch]

On systems using NetworkManager, there's [nm-openvpn-auth] process
running. The present test for openvpn matches such a process and
fails to connect. Adding --exact fixes the problem as it matches
only "openvpn" processes (exactly).

[mrtnmch]

Note this is an equivalent of the PR I submitted for the previous version (ProtonVPN/protonvpn-cli#192). I used --exact instead of -x for better readability.

[Rafficer]

Thank you! This will make it into the next version, which will likely only be bug fixes :)

[Rafficer]

I just noticed that --exact was added after -x. I think somewhere around v3.3 of procps.

All current distros definitely have that option (see https://pkgs.org/download/procps-ng), only distros without it I could find that might be used are RHEL/CentOS 6 and SLES 11. Since those are in no way consumer distros (and pretty much EOL anyway), I'd personally say f**k it and leave it as it is, using --exact. But I thought I'd mention it just to get other opinions as well.

So if someone thinks it should be -x for this reason, speak up 🙂

[kaplun]

I think we can pretty much support modern distributions :-)