[MERGE] [FIX] mail: mail: backport of saas-2 revision 9065 and 9081 and security...

[MERGE] [FIX] mail: mail: backport of saas-2 revision 9065 and 9081 and security improvements.

Add followers before super call in mail_thread creation.
This allows to have a value for the _set_followers call and be able to have record rules based on followers at creation.

Set the priority of message_follower_ids fields to -10 (default is 0) to be sure it will be executed before other function fields using these followers (eg: _set_stage_per_user from note.note does a browse which would trigger record rules to read the note)

Context hack to avoid checking read access at creation of the record (check create rules instead)

lp bug: https://launchpad.net/bugs/1259913 fixed

bzr revid: mat@openerp.com-20140206121438-epghqo042ync24v5