Updated openstack/openstack
Project: openstack/requirements  51342136bf2118c39a621f4d8cb5b30a4c11da2a

Increase sphinx pin now that 1.2.1 is out

1.2.1 fixes the bug that was in 1.2 - so we should go ahead and update.
Keep the pin at below 1.3 because sphinx breaks things.

Change-Id: I63c6159eb23430a181eb20016b35366c2fbbf9f8