misc_radius doc : more information freeradius-client

[ycaner06]

added information about how to active freeradius-client library

[oej]

Shall we really remove radiusclient-ng - is it a dead project?

Would it be possible to fix this in the makefile instead of suggesting a manual change?

[linuxmaniac]

fix the makefile?
we can switch the default to the newer one but we need a way to switch in order to support older distros

We already use this:
https://github.com/kamailio/kamailio/blob/master/pkg/kamailio/deb/jessie/rules#L23-L24

[oej]

So why are the doc files talking about radiusclient-ng and not FreeRadius?

[oej]

http://kamailio.org/docs/modules/devel/modules/auth_radius.html

[miconda]

I am not familiar with the distribution of freeradius client library, I know that at some moment was only available in latest opensuse or fedora. I am fine to switch to freeradius client lib as long as the latest stable popular os distros have it.

[miconda]

Merging the pull request, to get the commit in. If there is anything else to be sorted out, a new issue can be created.