[FIX] project_issue: fixed write of date_action_last: it is possible to post a messag...

[FIX] project_issue: fixed write of date_action_last: it is possible to post a message without having access to write access rights on an issue, therefore using SUPERUSER_ID (e.g. portal user).

[FIX] mail_message, mail, project, task, issue: it is now possible to have model-specific access rule checking for mail.message related acces right / rules. Task and issue allow to create mail.message when the user has a read access on the related document, not only when having write access.

bzr revid: tde@openerp.com-20130528144447-3ivcom6r9x7q949b