Provide tenant_id in Neutron create requests

Include the tenant_id explicitly in the Neutron object creation
requests rather than assuming that all of the information can
be derived from Keystone. This fixes deployments that only pass
tokens to Neutron.

Closes-Bug: #1400418
Change-Id: I10d50c202c7fd156455a97c6a5451225154ae0bc
Merge "Provide tenant_id in Neutron create requests"