Starting with oslo.db+Nova, we would like to specify say
oslo.db[fixtures] in Nova's test-requirements. If you see
the proposed review I4131e534d4cb12e4888d398fa4fb7c922e369210
the gate-nova-requirements fails because code in
project-config/jenkins/scripts/project-requirements-change.py
does not understand extras at all and treats both oslo.db
and oslo.db[fixtures] the same. Since that module
uses requirement.py, we should expose the information here
first and then fix project-config after that.
Change-Id: I146baa3ef94cc8bbf29af371786f3ea95a42cb9f
33636c1d81