Make "/etc/rc.d/syscons start" correctly reload screensaver settings.

The code looks for all the loaded screensaver modules, tries to
kldunload them, and only loads the new one if kldstat's output shows
that there aren't any left. However, the regexp looking for modules
to unload was still searching according to the the old naming scheme,
splash_<name>.ko, instead of <name>_saver.ko.

MFC after: 3 days