1158138, 1113629 - Allow '.' in logins, permissions

Adding the ability to add '.' in the username
Something strange is happening on the migrate.

    ± pulp-admin auth permission list --resource /
     +----------------------------------------------------------------------+
                                Permissions for /
     +----------------------------------------------------------------------+

    Admin:  CREATE, READ, UPDATE, DELETE, EXECUTE

Then I checked out your pr, ran the migration, and restarted.

     ± pulp-admin auth permission list --resource /
     +----------------------------------------------------------------------+
                               Permissions for /
    +----------------------------------------------------------------------+

Permissions are gone and I suspect it might have to do with this line.  Drilling in a little I see that `permission['users']` is a list, not a dict.

    [{u'username': u'admin', u'permissions': [1, 2]}]