Cannot uninstall a module (5.0)

[Dukai Gábor]

Hi!
5.0 latest bzr.
I get an error trying to uninstall a module (koo).

 Exception in call: Traceback (most recent call last):
   File "bin/wizard/__init__.py", line 73, in execute_cr
     action_res = action(self, cr, uid, data, context)
   File "bin/addons/base/module/wizard/wizard_module_upgrade.py", line 92, in _upgrade_module
     db, pool = pooler.restart_pool(cr.dbname, update_module=True)
   File "bin/pooler.py", line 62, in restart_pool
     return get_db_and_pool(db_name, force_demo, status, update_module=update_module)
   File "bin/pooler.py", line 40, in get_db_and_pool
     addons.load_modules(db, force_demo, status, update_module)
   File "bin/addons/__init__.py", line 768, in load_modules
     pool.get(rmod).unlink(cr, uid, [rid])
 AttributeError: 'NoneType' object has no attribute 'unlink'