Insert client connection data into PAM environment, upgraded

[wardragon]

Thank you for your contribution

You are welcome to open PR, but they are used for discussion only. All patches must eventually go to the openvpn-devel mailing list for review:

• https://lists.sourceforge.net/lists/listinfo/openvpn-devel

Please send your patch using git-send-email. For example to send your latest commit to the list:

$ git send-email [email protected] HEAD~1

For details, see these Wiki articles:

• https://community.openvpn.net/openvpn/wiki/DeveloperDocumentation
• https://community.openvpn.net/openvpn/wiki/Contributing