Issue 6099 - systemd = False has no effect

[vashirov]

Bug Description:
systemd = False doesn't override with_systemd = 1 from defaults.inf when used with dscreate. It is only effective when setup is running in a containerized environment (via dscontainer). But for some special use cases it's important that DS installation runs without systemd.

Fix Description:
Remove the condition for overriding systemd flag.
systemd option is not exposed in the default template, it's listed there only when --advanced flag is used, so it should not affect regular installations.

Fixes: #6099

[vashirov]

dscreate tests in the basic test suite fail because of the assert in the try..except block, it prevents finalizer to run to clean up and remove the instance before the next test. Working on the tests fix...

[vashirov]

This uncovered another issue: server can't be stopped, if it was created with systemd = False. ns-slapd keeps running, because lib389 has no idea that the override existed when the instance was created, and tries to stop it using systemd (because with_systemd = 1 is in the defaults.inf). And we don't expose this in .dsrc.