Enable the native memlockd systemd unit file.
Set memlockd.service's OOMScoreAdjust to -17.

We don't want *this* service to be killed by the OOM killer.
Adjust some bits of the manual test suite for Jessie.
Don't load acpi-cpufreq at boot time.

It fails to load whenever no device it supports is present, which makes the
systemd-modules-load.service fail. Anyway, these days, the kernel should just
automatically load such modules when they are needed.

(We started loading this module five years ago, in commit e6aaca8.)