Systemd split variables when specified like $VAR and not when specified
like ${VAR}. Since OPTS must contain multiple options, we must ensure
systemd will split it.
See also systemd.service(5)
Update the spec file with the rpm macro to put the unit file
in the system-wide unit file directory based on:
[root@1713bbf19a0b /]# rpmbuild --eval '%{_unitdir}'
/usr/lib/systemd/system
Allow user to create a drop directory to specify options
via environment variables.
Resolves https://github.com/purpleidea/mgmt/issues/12.