Code review comment for lp://staging/~bac/launchpad/bug-410416

= Summary =

An oversight was discovered in that private teams can not play the role of project
owner or driver, which was filed as Bug 410416.

In the process of making the fix it was discovered that creating a project also makes
the trunk productseries with the same owner. So productseries owner and driver were
also changed to allow private teams.

== Proposed fix ==

Change the type and validators for those properties to allow private teams.

== Pre-implementation notes ==

None.

== Implementation details ==

As above.

== Tests ==

bin/test -vvm lp.registry -t private-team-roles.txt

== Demo and Q/A ==

QA would be to create a private team on staging and ensure can become a project owner
and driver. Same for a product series.

= Launchpad lint =

Checking for conflicts. and issues in doctests and templates.
Running jslint, xmllint, pyflakes, and pylint.
Using normal rules.

Linting changed files:
  lib/lp/registry/model/productseries.py
  lib/lp/registry/doc/private-team-roles.txt
  lib/lp/registry/interfaces/product.py
  lib/lp/registry/interfaces/productseries.py
  lib/lp/registry/model/product.py

== Pyflakes notices ==

lib/lp/registry/model/productseries.py
    37: 'validate_public_person' imported but unused

== Pylint notices ==

lib/lp/registry/model/productseries.py
    37: [W0611] Unused import validate_public_person

This import will be removed before landing.