[web] Don't raise ProcessFormError if there is no value specified
a03376213747 introduced a slight modification in None / empty string values and
with it a regression where an exception is raised on empty values, while we
should simply consider no value is specified and return None.
.. _core_module:
:mod:`cubicweb.pyramid.core`
----------------------------
.. automodule:: cubicweb.pyramid.core
.. autofunction:: includeme
.. autofunction:: cw_to_pyramid
.. autofunction:: render_view
.. autofunction:: repo_connect
.. autofunction:: get_principals
.. autoclass:: CubicWebPyramidRequest
:show-inheritance:
:members:
.. autofunction:: _cw_session
.. autofunction:: _cw_cnx
.. autofunction:: _cw_request