Update rc.conf.pcbsd

Adding avahi-daemon and avahi-dnscond to fastboot_earlyrc= will fix Gnome 3 issues with fastboot.  Otherwise if a user logs in before those services have started they will not have a wallpaper, it may log them out when keyring appears, and they will be unable to logout without restarting PCDM.
Merge pull request #1 from pkgdemon/patch-1

Update rc.conf.pcbsd