This change moves the SHA for oepnstack global requirements.

The reason for this change is to update python package versions.
@miguelgrinberg found that an upstream commit in global requirements
was made to ensure nova is not 100% broken, IE: commit message
"block sqlalchemy migrate 0.9.2 as it breaks all of nova".

Reason for change : https://github.com/openstack/requirements/commit/c312e42b9170172f4a8be5aadf0e4d4dae88b22b