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.
def test_selection(self):
        [record] = self.Model.browse(self.cr, self.uid, [self.Model.create(self.cr, self.uid, {
            'selection': 2,
            'selection_str': 'C',
        })])
        converter = self.registry('ir.qweb.field.selection')
        field_name = 'selection'
        value = converter.record_to_html(self.cr, self.uid, field_name, record)
        self.assertEqual(value, "réponse B")
        field_name = 'selection_str'
        value = converter.record_to_html(self.cr, self.uid, field_name, record)
        self.assertEqual(value, "Qu'est-ce qu'il fout ce maudit pancake, tabernacle ?")
class TestHTMLExport(TestBasicExport):
    def test_html(self):
        converter = self.get_converter('html')
        input = '<span>span</span>'
        value = converter(input)
        self.assertEqual(value, input)
class TestDatetimeExport(TestBasicExport):
    def setUp(self):
        super(TestDatetimeExport, self).setUp()
        # 
        Users = self.registry('res.users')
        Users.write(self.cr, self.uid, self.uid, {
            'tz': 'Pacific/Niue'
        }, context=None)
    def test_date(self):