The server was not starting.  As a result, the dnsmasq service failed to
start, and the playbook thus failed to run when using the vpn role.
This patch corrects the configuration per instructions from
https://help.ubuntu.com/community/OpenVPN.

OpenVPN PAM configuration moved up to reduce server bouncing as the
playbook runs.  The dependency on service (re)starts between openvpn and
dnsmasq works but feels brittle.