[7.0] test hr_holidays/test/hr_holidays_report.yml fails when run in August

When this YAML tets in run in august, it fails:

UnicodeDecodeError('ascii', '<date month="ao\xfbt" year="2013" />', 15, 16, 'ordinal not in range(128)')
Stacktrace

Traceback (most recent call last):
  File "C:\Jenkins\vlabus_test\openerp\addons-external\vlabus_smile_test\smile_test.py", line 166, in test
    self._run_test(new_cr, module_name, filename)
  File "C:\Jenkins\vlabus_test\openerp\addons-external\vlabus_smile_test\smile_test.py", line 74, in _run_test
    tools.convert_yaml_import(cr, module_name, open_file, kind='test', idref=None, mode='update', noupdate=False)
  File "C:\Jenkins\vlabus_test\openerp\openerp-server\openerp\tools\yaml_import.py", line 928, in yaml_import
    yaml_interpreter.process(yaml_string)
  File "C:\Jenkins\vlabus_test\openerp\openerp-server\openerp\tools\yaml_import.py", line 864, in process
    self._process_node(node)
  File "C:\Jenkins\vlabus_test\openerp\openerp-server\openerp\tools\yaml_import.py", line 877, in _process_node
    self.process_python(node)
  File "C:\Jenkins\vlabus_test\openerp\openerp-server\openerp\tools\yaml_import.py", line 550, in process_python
    unsafe_eval(code_obj, {'ref': self.get_id}, code_context)
  File "C:\Jenkins\vlabus_test\openerp\openerp-server\openerp\addons\hr_holidays\test\hr_holidays_report.yml", line 6, in <module>
    ctx={}
  File "C:\Jenkins\vlabus_test\openerp\openerp-server\openerp\tools\test_reports.py", line 294, in try_report_action
    result = _exec_action(action, datas, context)
  File "C:\Jenkins\vlabus_test\openerp\openerp-server\openerp\tools\test_reports.py", line 278, in _exec_action
    res = try_report(cr, uid, 'report.'+action['report_name'], ids, datas, context, our_module=our_module)
  File "C:\Jenkins\vlabus_test\openerp\openerp-server\openerp\tools\test_reports.py", line 53, in try_report
    res = netsvc.LocalService(rname).create(cr, uid, ids, data, context)
  File "C:\Jenkins\vlabus_test\openerp\openerp-server\openerp\report\interface.py", line 83, in create
    xml = self.create_xml(cr, uid, ids, datas, context)
  File "C:\Jenkins\vlabus_test\openerp\openerp-server\openerp\addons\hr_holidays\report\holidays_summary_report.py", line 203, in create_xml
    date_xml = ''.join(date_xml)
UnicodeDecodeError: 'ascii' codec can't decode byte 0xfb in position 15: ordinal not in range(128)