This reverts commit f29dae997ac26e5fcbd2eb037ed42028e54f2a6d.

This is usefull to control the order of how lxc.conf will
be written (especially for lxc.network.* values)

Mybad, OrderedDict is not needed, moreover it reduces
performances.

This way, once the container is created, even if slapcontainer
fail to start it ; slapcontainer_conf will be written.

Conflicts:
	CHANGES.txt

Conflicts:
	CHANGES.txt
	setup.py

Reuse erp5.util.taskdistribution for better TaskDistributionTool
integration (adds a dependency, removes 2 entry points): it is possible to
create several test agents with same configuration, each testing a subset
of the entire test suite. Especially useful if/when test agents gets the
extra task of monitoring commits on software releases, and they locally
build & instanciate the SR they test.
Use a medium-lived process rather than a short-lived one, to drop state
loading & saving complexity.
Allow a single test agent to run several concurrent tests.
Cleanup pidfile, even when exceptions occur.
Factorise code used to test each step.
Rework configuration file layout, to better use magic "[DEFAULT]" section.
Take keys & certs from configuration file, allowing for per-test certs.
Remove the need for storing using login & password by reusing x509 auth.