Well, I found a quick fix for the broken easy-rsa download if anyone wants to use it. It worked for my system but I don't know if it will work for yours (although it should).
1) Go to your the scripts directory in your plugin installation directory it should be located in:
/usr/local/emhttp/plugins/openvpnserver/scripts
2) Use nano (or your favorite text editor) to edit the rc.openvpnserver script.
3) Using your text editor scroll down until you hit a function called "openvpnserver_get_easy", in this function you will want to make the following changes:
delete or comment out:
wget $EASYRSA_DL_VERSION line, this command is causing problems since an earlier curl does not work properly.
replace this line with this command:
wget "https://github.com/OpenVPN/easy-rsa/archive/master.zip"
And, that's it!.
After you save the script you can run the following command to download easy rsa, or you could click on the GUI's button. Your choice:
./rc.openvpnserver download_easy-rsa
It is worthy to note that this is a more or less patchwork solution, while it works now I do not know how long it will remain that way. If you have any suggestions or questions, leave a response.
Good luck!.