[dataimport] fix db-namespace default value handling In a fresh new instance, the "db-namespace" option is set as empty by default in the "sources" file. This seems correct but empty string is not a valid pg_schema and actually means that we should use "public"

.. _req_module:

:mod:`cubicweb.req`
===================

.. automodule:: cubicweb.req

    .. autoexception:: FindEntityError

    .. autoclass:: RequestSessionBase
        :members: