Impacted versions: 9.0, 9.0 enterprise

Steps to reproduce:
On current runbot duplicate any posted journal entry which is balanced

Current behavior:
Error message "Cannot create unbalanced entry" is shown

Expected behavior:
New Journal entry is created in state 'draft'

Video/Screenshot link (optional):
![selection_268](https://cloud.githubusercontent.com/assets/14974044/15007437/41f45a56-11d9-11e6-84f3-b297befaa521.png)

is_partner and 'partner_id, partner_name,' or ' ',
                is_partner and 'p.id AS partner_id, p.name AS partner_name,' or ' ',
                is_partner and 'RIGHT JOIN res_partner p ON (l.partner_id = p.id)' or ' ',
                is_partner and ' ' or "AND at.type <> 'payable' AND at.type <> 'receivable'",
                account_type and "AND at.type = %(account_type)s" or '',
                res_ids and 'AND ' + res_alias + '.id in %(res_ids)s' or '',
                self.env.user.company_id.id,
                is_partner and 'AND l.partner_id = p.id' or ' ',
                is_partner and 'l.partner_id, p.id,' or ' ',
                res_alias=res_alias
            ))
        self.env.cr.execute(query, locals())
        
        rows = self.env.cr.dictfetchall()
        ids = [x['account_id'] for x in rows]
        allowed_ids = set(self.env['account.account'].browse(ids).ids)
        rows = [row for row in rows if row['account_id'] in allowed_ids]
        if is_partner:
            ids = [x['partner_id'] for x in rows]
            allowed_ids = set(self.env['res.partner'].browse(ids).ids)
            rows = [row for row in rows if row['partner_id'] in allowed_ids]
        
        for row in rows:
            account = self.env['account.account'].browse(row['account_id'])
            row['currency_id'] = account.currency_id.id or account.company_id.currency_id.id
            partner_id = is_partner and row['partner_id'] or None
            row['reconciliation_proposition'] = self.get_reconciliation_proposition(account.id, partner_id)
        return rows
    @api.model
    def get_reconciliation_proposition(self, account_id, partner_id=False):