Fix flake8 errors/warnings about import in cubicweb/_exceptions.py
We either ignore errors in case of name re-exports and drop re-exports
from old backwards compatibility. We fix the only occurrence of
NoSelectableObject being imported from cubicweb in tests and update the
import to use lgc instead.
.. _req_module:
:mod:`cubicweb.req`
===================
.. automodule:: cubicweb.req
.. autoexception:: FindEntityError
.. autoclass:: RequestSessionBase
:members: