Issue Summary

Cannot remove all default space permissions if there was a group with Admin permissions.

Steps to Reproduce

1. Go to General Configuration->Space Permissions
2. Delete all groups except one
3. for the remaining group add Admin permissions
4. Save
5. Try removing this permission.

Expected Results

The last group should be possible to delete.

Actual Results

After having at least one group with default admin rights it is impossible to delete all of them anymore.

Workaround

Delete the group from the DB record.

If you just want to delete the group you will need to add another group with Admin access (for example confluence-administrators)