remove a tab, as pointed out on IRC Daniel

* python/libxml2.py: remove a tab, as pointed out on IRC
Daniel
diff --git a/python/libxml.py b/python/libxml.py
index 0c2a19a..997e15f 100644
--- a/python/libxml.py
+++ b/python/libxml.py
@@ -212,7 +212,7 @@
 
     def warning(self, msg):
         #print msg
-	pass
+        pass
 
     def error(self, msg):
         raise parserError(msg)