openbsd: cleanups and sync with ConsoleKit port

We never needed to use an external helper script with the original
ConsoleKit for ck-get-x11-*, so drop these.
Make sure we install the other tools and simplify the scripts in the
process.
Merge pull request #14 from ajacoutot/openbsd-port-sync

openbsd: cleanups and sync with ConsoleKit port
Fix pam-foreground-compat install

The pam-foreground-compat.ck script should be installed without
requring udev.