Some legacy clouds (e.g. mine) still have some projects with
legacy project ids that don't conform to the uuid requirement.
This is an extremely obscure edge case, but this API is the only
one I've seen in all of OpenStack that rejects malformed
project ids.
Changing to a more lenient check fixes my immediate
problem and also establishes greater consistency with other APIs.
Change-Id: I27e697e7e6818b120f745641cbc8d7daed2bd7b0