Bug 1292494

+++ This bug was initially created as a clone of Bug #1292157 +++

Description of problem:
Deletion of tenant is allowed when there is group with this tenant assigned. This will cause that group will loose tenant membership. This is e.g. breaking Automate-Explorer.

Version-Release number of selected component (if applicable):
5.5.0.13

How reproducible:
always

Steps to Reproduce:
1. Create tenant1
2. Create new group called tenant1, assign super administrator role to it and tenant1 tenant
3. Create new user tenant1 and assign him into tenant1 group
4. Login as tenant1 
5. navigate to Automate -> Explorer

Actual results:
You will see this message on the screen:
We're sorry, but something went wrong.
We've been notified about this issue and we'll take a look at it shortly.

When you navigate to tenant1 group, there is no tenant assigned to this group, which is mandatory when creating new group.

In order to fix this, login as super administrator of My Company tenant and assign tenant to tenant1 group.

Also noticed that user which is not member of any tenant can login into CFME.

Expected results:
Tenant/child tenant/project cannot be deleted if there is group which is relying on this tenant/project.
This check should be implemented also for all child tenants.
Similar check is done when you try delete group which has members in it.

Additional info: