Pin SQLAlchemy to 0.7.x

0.7.10 has been released and is compatible with 0.7.x. Instead
of pinning to 0.7.9, simply pin to 0.7.x to avoid SQLAlchemy 0.8

Also sync the 0.7.x requirements to 0.7 (to be in sync with other
OpenStack core components)

Fixes: Bug #1153983

Change-Id: Ie20344e96f3d12e93695579adff0a0d9b4c1c516
Merge "Pin SQLAlchemy to 0.7.x"