Description of problem:
If the last Spacewalk admin has the organization admin role removed, and is then deactivated, it can then be deleted by an organization administrator in the same org.

This leaves Spacewalk with no admin accounts. It is then not possible to create a new Spacewalk admin account or grant the Spacewalk admin role to another user.

Version-Release number of selected component (if applicable):
All

How reproducible:
Web UI, spacecmd and xmlrpc

Steps to Reproduce:
Example from web UI:

Assume two users, sw_admin and org_admin, both in org1. 

sw_admin is both a Spacewalk admin and an org_admin for org1. 
org_admin is only an org admin for org1.

1. Login as org_admin
2. Remove Organization Administrator role from sw_admin
3. Deactivate sw_admin user
4. Delete sw_admin user

Actual results:
Last admin user is deleted.

Expected results:
Should be told it's not permissable to delete the last Spacewalk admin. This is the current behaviour if the account was active.