sw: small code refactor

Created method DocxAttributeOutput::pushToAttrList which encapsulates
a piece of code that was widely repeated in that class:

  if( some attribute list does not exist )
      create the list

  push some value to the list
  push some other value to the list

Change-Id: Ia648802f5237bd7c97bf225d33b305dbef1b72dd

sw/source/filter/ww8/docxattributeoutput.hxx

@@ -672,6 +672,9 @@ private:
     void CmdField_Impl( FieldInfos& rInfos );
     void EndField_Impl( FieldInfos& rInfos );
 
+    void pushToAttrList( ::sax_fastparser::FastAttributeList **pAttrList, sal_Int32 nAttrName, const sal_Char* sAttrValue );
+    void pushToAttrList( ::sax_fastparser::FastAttributeList **pAttrList, sal_Int32 nArgs, ... );
+
     ::sax_fastparser::FastAttributeList *m_pFontsAttrList, *m_pEastAsianLayoutAttrList;
     ::sax_fastparser::FastAttributeList *m_pCharLangAttrList;
     ::sax_fastparser::FastAttributeList *m_pSectionSpacingAttrList;