This fix allows to run 389-DS CI tests when 389-ds is deployed as a rpm.

It takes into account previous remarks done by Rich (no use of 'sudo' or 'systemctl').
The tests can be launched either being 'root' ('cd ds/dirsrvtests/tickets; py.test ') or with sudo ('cn ds/dirsrvtests/tickets; sudo py.tests').

Currently some ticket tests are failing. This is because those tests need to be fixed regarding master branch.
Fixing those tests will be done with a separate ticket.