Remove missing import (since b62968cd2666)

--HG--
branch : distribute
extra : rebase_source : d1190f895d794dfcb838f7eb40a60ab07b8b309e

_markerlib/__init__.py

 """Used by pkg_resources to interpret PEP 345 environment markers."""
-from _markerlib.markers import default_environment, compile, interpret, as_function
+from _markerlib.markers import default_environment, compile, interpret