fix issue, when structure data type with array field is created

Traceback (most recent call last):
File "editors/DataTypeEditor.py", line 669, in ElementArrayTypeFunction
self.RefreshTypeInfos()
File "editors/DataTypeEditor.py", line 761, in RefreshTypeInfos
self.Controler.SetDataTypeInfos(self.TagName, infos)
File "PLCControler.py", line 2075, in SetDataTypeInfos
array.baseType.setcontent(PLCOpenParser.CreateElement(
AttributeError: 'lxml.etree._Element' object has no attribute 'setcontent'

<?xml version='1.0' encoding='utf-8'?>
<BeremizRoot URI_location="LOCAL://">
  <TargetType/>
</BeremizRoot>