Fix non zero rate unittest

(transplanted from f4a6bbba2d2f49ebd00522b9ab17d01d54f7c823)

tests/test_product.py

@@ -66,17 +66,17 @@ class ProductTestCase(unittest.TestCase):
                 })
             transaction.cursor.commit()
 
-            self.failUnlessRaises(Exception, self.uom.write, {
+            self.failUnlessRaises(Exception, self.uom.write, category_id, {
                 'rate': 0.0,
                 })
             transaction.cursor.rollback()
 
-            self.failUnlessRaises(Exception, self.uom.write, {
+            self.failUnlessRaises(Exception, self.uom.write, category_id, {
                 'factor': 0.0,
                 })
             transaction.cursor.rollback()
 
-            self.failUnlessRaises(Exception, self.uom.write, {
+            self.failUnlessRaises(Exception, self.uom.write, category_id, {
                 'rate': 0.0,
                 'factor': 0.0,
                 })