[IMP] use a single thread for crons (forwardport of 2123 chs@openerp.com-20100920112005-hk9zrgpbx9m0w6tv from 5.0 branch)
[IMP] use a single thread for crons (forwardport of 2123 chs@openerp.com-20100920112005-hk9zrgpbx9m0w6tv from 5.0 branch)

akretion/openerp-server,akretion/openerp-server,akretion/openerp-server