Allow to spawn instances in provisioning network

[Vasyl Saienko]

Currently building instances in ironic provisioning network is not working and no proper message is showed. It doesn't work due to several reasons:

1. When we are adding ports to provisioning network we expecting that there is no instance ports.
2. At the end of deployment we always removing provisioning ports.

By allowing build instances in provisioning network we break idea of multitenancy itself and backing to flat scenario. My feeling that we shouldn't allow use provisioning network for instances and fail with proper error message.

Looking for other thought on this.

[Jay Faulkner (jason-oldos)]

I agree, we should explicitly disallow this rather than it failing late.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/397517
Committed: https://git.openstack.org/cgit/openstack/ironic/commit/?id=75b90a5ddb249b8ce9c5dc4a4acf95c3040e76c1
Submitter: Jenkins
Branch: master

commit 75b90a5ddb249b8ce9c5dc4a4acf95c3040e76c1
Author: OctopusZhang <[e-mail]>
Date: Tue Nov 15 12:01:44 2016 +0800

    Update multitenancy docs

    Add a warning to remind user to configure provisioning and cleaning
    network as non-shared network.

    Add a note to remind user not to use provision network for instance
    spawning.

    Change-Id: Ifd7218fc24386097ed072195de8712d600399f09
    Related-Bug: #1634573

[Hao Li (lihaosz)]

@Vasyl Saienko (vsaienko)
I always meet this problem, I think we can throw exception when ironic conductor create provision_network_port instead of now meet error when deploy is nearly success, during the function configure_tenant_networks.