Comment 24 for bug 1250866

So, this bug was closed over 6months ago and you should have all the knobs necessary to configure things to specify the correct network when creating a server. It is quite likely the issue you're hitting is just a tempest configuration issue. I recommend reading:

http://docs.openstack.org/developer/tempest/configuration.html#networking

which covers how to configure tempest in different network configurations.

If you still have trouble I recommend asking in the #openstack-qa IRC channel and we can work through specifically what is happening in your use case.