use preferred section category instead of defined one

bt5/erp5_payroll/SkinTemplateItem/portal_skins/erp5_payroll/AccountingTransactionModule_getPaySheetMovementMirrorSectionItemList.xml

@@ -57,7 +57,7 @@ getobject = portal.portal_catalog.getobject\n
 for x in portal.portal_simulation.getInventoryList(\n
                               portal_type=(\'Pay Sheet Cell\',\n
                                            \'Pay Sheet Line\'),\n
-                              section_category=\'group/demo_group\',\n
+                              section_category=portal.portal_preferences.getPreferredAccountingTransactionSectionCategory(),\n
                               group_by_resource=0,\n
                               group_by_section=0,\n
                               group_by_mirror_section=1):\n

product/ERP5/tests/testPayroll.py

@@ -91,6 +91,10 @@ class TestPayrollMixin(TestTradeModelLineMixin, ERP5ReportTestCase):
     self.createCategories()
     self.fixed_quantity = self.setBaseAmountQuantityMethod('fixed_quantity',
       "return lambda *args, **kw: 1")
+    default_pref = self.portal.portal_preferences.default_site_preference
+    if default_pref.getPreferenceState() == 'disabled':
+      default_pref.enable()
+    default_pref.setPreferredAccountingTransactionSectionCategory('group/demo_group')
     self.setPayrollBaseAmountQuantityMethod("base_amount/payroll/base/contribution",
                                             """\
   def getBaseAmountQuantity(delivery_amount, base_application,