Return current user/project for user/project show commands

If non-admin user attempts 'project show' or 'user show' on the currently
authenticated project or user return the information that is already in the
service catalog rather than throwing a Forbidden error.

Change-Id: Ieeb6eacf71a471e410fbd3c09e7871740547e890
Merge "Return current user/project for user/project show commands"