WebStyle: fix response status code
WebStyle: fix response status code

* Fixes setter and getter of SimulatedModPythonRequest status property
  that it uses Flask response instance.  (closes #1328)

Reported-by: Lars Holm Nielsen <7eaffca9f7cd98839b5821d0d23e09ff764b82cd@cern.ch>

inveniosoftware/invenio,tiborsimko/invenio,tiborsimko/invenio,inveniosoftware/invenio