bzr revid: vmt@openerp.com-20121206145632-0h1coh5aaem65wsy
[ADD] Check on 'None' context in account module's sequence override bzr revid: stefan@therp.nl-20120322113959-79wxzej9ih4igg28
bzr revid: al@openerp.com-20111001000455-opnivkh5nvvutv2y