Comment 0 for bug 1571878

Currently, it is possible to add a protocol to a identity provider [0] using a nonexistent mapping id. We could add a mapping using the ID in the previous step, but several errors can occur in between this steps.

We might want to enforce steps here:
1 - create idp
2 - create mapping
3 - create protocol

[0] https://github.com/openstack/keystone-specs/blob/master/api/v3/identity-api-v3-os-federation-ext.rst#add-a-protocol-and-attribute-mapping-to-an-identity-provider