Write access is required for creating an object with a chatter

When creating an object with a user that only has 'create' access for the relevant model, the creation fails with a 'no access to modify' exception if the model uses a chatter. Example model: hr.applicant.

This behavior changed recently, somewhere between these 2 versions:
- Version with the problem: 7.0-20130723-231040
- Version without the problem: 7.0-20130526-231028

Relevant lines in mail_message.py:
724 if operation in ['create', 'write', 'unlink']:
725 model_obj.check_access_rights(cr, uid, 'write') <-- THIS ONE
726 model_obj.check_access_rule(cr, uid, mids, 'write', context=context)