Avoid dictionary initialization during import in PouDialog

Because initialization happened before i18n setup, then it causes later
problems during creating new POU on non-English locales (Russian for example).

Traceback (most recent call last):
File "/home/developer/WorkData/PLC/beremiz/beremiz/IDEFrame.py", line 2332, in OnAddPouMenu
dialog = PouDialog(self, pou_type, type_readonly)
File "/home/developer/WorkData/PLC/beremiz/beremiz/dialogs/PouDialog.py", line 101, in __init__
self.RefreshLanguage()
File "/home/developer/WorkData/PLC/beremiz/beremiz/dialogs/PouDialog.py", line 154, in RefreshLanguage
if language != "SFC" or PouDialog.POU_TYPES_DICT[self.PouType.GetStringSelection()] != "function":
KeyError: u'\u043f\u0440\u043e\u0433\u0440\u0430\u043c\u043c\u0430'