Remove _getAttributeNames special case for completion

IPython/utils/dir2.py

@@ -48,8 +48,7 b' def dir2(obj):'
     """dir2(obj) -> list of strings
 
     Extended version of the Python builtin dir(), which does a few extra
-    checks, and supports common objects with unusual internals that confuse
-    dir(), such as Traits and PyCrust.
+    checks, and handles Traits objects, which can confuse dir().
 
     This version is guaranteed to return only a list of true strings, whereas
     dir() returns anything that objects inject into themselves, even if they
@@ -72,10 +71,8 b' def dir2(obj):'
 
 
     # for objects with Enthought's traits, add trait_names() list
-    # for PyCrust-style, add _getAttributeNames() magic method list
-    for attr in ('trait_names', '_getAttributeNames'):
         try:
-            func = getattr(obj, attr)
+        func = getattr(obj, 'trait_names')
             if callable(func):
                 words |= set(func())
         except: