[FIX] orm.search: fix ordering when multiple order columns are used
[FIX] orm.search: fix ordering when multiple order columns are used

Original refactoring forgot to properly fix the split, 
in revision 3143.1.2 revid:odo@openerp.com-20101221192344-87d7ajnfsn5unm9p

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