Create tmp file dir to enable pid creation between reboots

[mmeloni]

Create tmp file dir at every reboot
Correct docs

With the adoption of systemd as of 15.04, there is now a centralized mechanism for the creation of temporary files and directories such as these. A service wishing to use this method can remove mkdir commands in its own startup script and instead place a .conf file in /etc/tmpfiles.d, /run/tmpfiles.d, or /usr/lib/tmpfiles.d, with Ubuntu services seeming to prefer the last option. For example, my system now has:

$ egrep -r /var/run /usr/lib/tmpfiles.d

/usr/lib/tmpfiles.d/var.conf:L /var/run - - - - ../run
/usr/lib/tmpfiles.d/sudo.conf:d /var/run/sudo 0711 root root
/usr/lib/tmpfiles.d/sudo.conf:D /var/run/sudo/ts 0700 root root
/usr/lib/tmpfiles.d/postgresql.conf:d /var/run/postgresql 2775 postgres postgres - -
/usr/lib/tmpfiles.d/sshd.conf:d /var/run/sshd 0755 root root
/usr/lib/tmpfiles.d/screen-cleanup.conf:d /var/run/screen 0775 root utmp
The d means to create a directory if it doesn't already exist, after that is the path, and the rest are the permissions, user, and group. These directories will be created regardless of whether the corresponding service is ever started.

http://manpages.ubuntu.com/manpages/xenial/en/man5/tmpfiles.d.5.html