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.
openerp/addons/test_converter/tests/test_html.py
def test_integer(self):
        converter = self.get_converter('integer')
        value = converter(42)
        self.assertEqual(value, "42")
class TestFloatExport(TestBasicExport):
    def setUp(self):
        super(TestFloatExport, self).setUp()
        self.registry('res.lang').write(self.cr, self.uid, [1], {
            'grouping': '[3,0]'
        })
    def test_float(self):
        converter = self.get_converter('float')
        value = converter(-42.0)
        self.assertEqual(value, u"\u201142.0")
        value = converter(42.0100)
        self.assertEqual(value, "42.01")
        value = converter(42.01234)
        self.assertEqual(value, "42.01234")
        value = converter(1234567.89)
        self.assertEqual(value, '1,234,567.89')
    def test_numeric(self):
        converter = self.get_converter('numeric')
        value = converter(42.0)
        self.assertEqual(value, '42.00')
        value = converter(42.01234)
        self.assertEqual(value, '42.01')
class TestCurrencyExport(TestExport):