Better handling of /var directory.

[WayneBooth]

I was going to send another pull request for this but I noticed that
Gentoo sets localstatedir to be /var/lib rather than just /var so it was
creating /var/lib/run and /var/lib/log/opendias, which obviously isn't
right. I looked to see what some other packages do about /var/run but
they seem to leave this as a run-time configurable option for the
distributions to set. Furthermore, /var/run is now deprecated in favour
of /run. The former is now a symlink on my system.

http://lwn.net/Articles/436012