Use default_project_id as user project for keystone v3

This fixes the keystone api module so that it looks for the
default_project_id attribute on the user and uses that as the
primary project.

Closes-Bug: 1347840
Change-Id: If3ea4625ae50ae4561df3e566d1236b86226307b
Merge "Use default_project_id as user project for keystone v3"