Astng will try to find the right encoding and provide the right "stream"
interface for the Pylint checkers.
Reading a stream with the wrong encoding in py3k will generate a UnicodeError.
The introduced a 'F0010' failure should maybe be replaced by E0501, E0502 and
F0002? However, can we call 'unexpected errors' the ASTNGBuildingExceptions
that we raise in logilab.astng.builder?