These are currently only used inside this package, so we might
as well un-export them until we need them elsewhere.
Also updated SetOOMScore() to first check for privileged; check for privileged
looks to be the "faster" path, and checking it first could (in case of non-
privileged) save having to read and parse /proc/self/uid_map.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
