This is a conversion of sd_booted() from libsystemd to go and checks
if the system was booted with systemd.
Docker-DCO-1.1-Signed-off-by: Alexander Larsson <alexl@redhat.com> (github: alexlarsson)
Upstream-commit: 1296d5ce9ad43d8d833f6e5661da45aef6d4c26b
Component: engine
