[FIX] sale_timesheet: avoid currency rate based on demo data

On the 6 June, the rate from EUR to USD change
in demo data. This cause problem in test, when
comparing amount.

We choose to not used currency rate defined in
demo data and that are time-dependent.

addons/sale_timesheet/tests/test_timesheet_revenue.py

@@ -8,6 +8,13 @@ class TestSaleTimesheet(TestSale):
 
     def setUp(self):
         super(TestSaleTimesheet, self).setUp()
+
+        # NOTE JEM
+        # The tests below are based on the `base.rateUSD` currency rate. It
+        # is required to remove the `base.rateUSDbis` to avoid rounding error
+        # after the 6 june of current year.
+        self.env.ref('base.rateUSDbis').unlink()
+
         # create project
         self.project = self.env['project.project'].create({
             'name': 'Project for my timesheets',