Issue #138: Inactive User Groups affecting permissions (conservancy/kallithea)

[Bosco Rama]

New issue 138: Inactive User Groups affecting permissions
https://bitbucket.org/conservancy/kallithea/issue/138/inactive-user-groups-affecting-permissions

Bosco Rama:

A group marked as inactive is still affecting permissions, specifically global defaults.
(we noticed this wrt ability to fork repos).

Kallithea version:   Current stable from repo

```
$ hg summ
parent: 5159:c44885d0e546 tip
 vcs: added proper windows quoting to git commands (Issue #135)
branch: stable
commit: 1 modified
update: (current)
```

How to reproduce:

1. Create a user group and turn off 'Active'
1. Turn off 'Inherit defaults' and Save
1. Add a user which inherits defaults to the user group.

When you inspect user's permissions you'll notice that globally active defaults are deactivated for the user even though the group is not active.