Don't assume either namespace is not-None

jedi/parsing_representation.py

@@ -333,7 +333,7 @@ def _enables_absolute_import(imp):
     Checks if the import is a ``__future__`` import that enables the
     ``absolute_import`` feature.
     """
-    if imp.namespace is None:
+    if imp.from_ns is None or imp.namespace is None:
         return False
 
     namespace, feature = imp.from_ns.names[0], imp.namespace.names[0]