Use Easy-RSA 2.2.2 instead of the master branch with Debian Jessie and Ubuntu Saucy

This was needed for Debian Jessie, but using always the latest Easy-RSA
was a bad idea.

I will force Easy-RSA 2.2.2 for now and until Jessie becomes stable.
Then we can probably just use the distro packages instead of Github,
but for now this will work.
Bugfix for systems with multiple IPv4 addresses available