Updated openstack/openstack
Project: openstack/taskflow  d43cc4f9c33a37d6a3a3f1a1eec7219a0804767b

Move some of the custom requirements out of tox.ini

This change removes the need for an optional-requirements
file which isn't being kept up to date with the rest of the
openstack ecosystem and moves most of the customizations to
test-requirements and where different versions are still
needed (aka for SQLAlchemy) we place those varations into
there needed tox environment as required.

Change-Id: I443794b83de3f6a196fa7fc29a90620fb51b7f4c