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'?>
<PyFile xmlns:xhtml="http://www.w3.org/1999/xhtml" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <variables/>
  <globals>
    <xhtml:p><![CDATA[]]></xhtml:p>
  </globals>
  <init>
    <xhtml:p><![CDATA[]]></xhtml:p>
  </init>
  <cleanup>
    <xhtml:p><![CDATA[]]></xhtml:p>
  </cleanup>
  <start>
    <xhtml:p><![CDATA[]]></xhtml:p>
  </start>
  <stop>
    <xhtml:p><![CDATA[]]></xhtml:p>
  </stop>
</PyFile>