lmbench: specify configuration for systemd-tmpfiles --update

Running systemd-tmpfiles --update without specifying a configuration
file results in all tmpfiles.d configuration files being processed.

/usr/lib/tmpfiles.d/systemd.conf creates /run/nologin on boot to
prevent non-root users from logging in while the system is booting.
If systemd-tmpfiles --update is run after the system has started,
it will still create /run/nologin which would prevent non-root users
from logging in with the message "System is booting up.".

Signed-off-by: Jonathan Liu <net147@gmail.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>