[httpdomain] Using empty :endpoints: leads to no documented flask endpoints
When using the autoflask extension with httpdomain 1.1.8 the following fails to generate any flask docs:
.. autoflask:: app.application:make_app() :endpoints:
If I omit the :endpoints: it works and generates docs for all my routes.
It seems that autohttp.flask's AutoflaskDirective.endpoints is getting the string "None" instead of a None when an empty :endpoints: is used.
Encountered this with sphinx 1.2b1 but could reproduce with 1.1.3.