reconcile_partial() return reconcile record id

It should be similar like it's done with reconcile(). That would help a lot when needs to make automatic partial reconciliations.
Merge pull request #633 from komsas/patch-1

account: Unify reconcile_partial and reconcile behaviour: return the account.move.reconcile id
Merge branch 'master' of https://github.com/odoo/odoo into master-linux64