Revert "Replace xml.dom.minidom.parse which is known to be vulnerable to XML attacks. (#3933)"

This reverts commit 74f227590e.

Expat doesn't like  ./data/achievements.xml ! Error= <type 'exceptions.NameError'>
( ("name 'defusedxml' is not defined",) )

data/po/extract_strings_from_XML.py

@@ -86,7 +86,7 @@ for file in filenames:
         isAchievements = True
         
     try:
-        doc = defusedxml.minidom.parse(file)
+        doc = xml.dom.minidom.parse(file)
     except Exception as ex:
         print "============================================"
         print "/!\\ Expat doesn't like ", file, "! Error=", type(ex), " (", ex.args, ")"