[strongSwan] how to reload strongswan.conf runtime

[Martin Willi]

> > configured bunch of parameters like wins, dns, radius server, retries
> > in the strongswan.conf, however any change in them requires
> > strongswan to be restarted.
> 
> No, there is no way to reload strongswan.conf without a restart.

I have pushed some changes to master today that brings strongswan.conf
reloading of keys in some plugins.

On SIGHUP, charon reloads strongswan.conf and triggers a reload()
operation an all registered plugins. Currently only the attr plugin and
the eap-radius plugin support reloading.

Some other keys are automatically reread during operation, but most are
not. We will extend reloading of other plugins/keys where appropriate.

Regards
Martin