Exclude constants from autodoc
Exclude constants from autodoc

Since the 2.1.0 release of Sphinx, the docs fail to build because of the
warnings-treated-as-errors of the now autodoc'd imported external
modules[1]. This change configures sphinx-autodoc to ignore those
constants so that the docs can build and the documentation from the
external modules isn't included in keystone's.

[1] https://github.com/sphinx-doc/sphinx/issues/6447

Change-Id: I7b1c2c740727446d5460dc0025e47e0e9b388d10

mahak/keystone,mahak/keystone,openstack/keystone,openstack/keystone,openstack/keystone,mahak/keystone