Impacted versions: ODOO 10

Problem.
If i print a invoice with a negative amount, the pdf shows a vertical bar instead of a minus symbol.
![image](https://cloud.githubusercontent.com/assets/28800797/26237253/b07fadb0-3c74-11e7-86c2-c8688d82b5a5.png)

I have tried to install a new pdf reader, but with no result.
_name = 'ir.qweb.field.contact'
    _inherit = 'ir.qweb.field.many2one'
    def record_to_html(self, cr, uid, field_name, record, options=None, context=None):
        if context is None:
            context = {}
        if options is None:
            options = {}
        opf = options.get('fields') or ["name", "address", "phone", "mobile", "fax", "email"]
        value_rec = record[field_name]
        if not value_rec:
            return None
        value_rec = value_rec.sudo().with_context(show_address=True)
        value = value_rec.name_get()[0][1]
        val = {
            'name': value.split("\n")[0],
            'address': escape("\n".join(value.split("\n")[1:])).strip(),
            'phone': value_rec.phone,
            'mobile': value_rec.mobile,
            'fax': value_rec.fax,
            'city': value_rec.city,
            'country_id': value_rec.country_id.display_name,
            'website': value_rec.website,
            'email': value_rec.email,
            'fields': opf,
            'object': value_rec,
            'options': options
        }
        html = self.pool["ir.ui.view"].render(cr, uid, "base.contact", val, engine='ir.qweb', context=context).decode('utf8')
        return HTMLSafe(html)
class QwebView(orm.AbstractModel):