Cleanup even more dead code
diff --git a/Lib/xml/etree/ElementTree.py b/Lib/xml/etree/ElementTree.py
index 9ea0dc8..eca1562 100644
--- a/Lib/xml/etree/ElementTree.py
+++ b/Lib/xml/etree/ElementTree.py
@@ -1682,10 +1682,3 @@
 except ImportError:
     pass
 
-
-# workaround circular import.
-try:
-    from ElementC14N import _serialize_c14n
-    _serialize["c14n"] = _serialize_c14n
-except ImportError:
-    pass