Updated openstack/openstack
Project: openstack/requirements  3dc2492f2e81424034218f299f6b9ab2d7d24a6b

add header warning against sorting requirements

During sync, add a header to the requirements files warning anyone
against changing the order of the contents, especially against sorting.

Addresses-Bug: #1365061
Change-Id: I64ae9191863564e278a35d42ec9cd743a233028e