In this scenario:

1. User has one organization - "E-Corp" - this organization allows the user to see every hostgroup (via selecting "all host groups" when editing the organization).
2. User has a location "Czech republic" that also includes all host groups through that checkbox.
3. User visits /hostgroups with "any context" selected, or "E-Corp/any location", or "any organization/Czech republic". The result is that the user does not see all host groups even though there's an organization/location combination (e-corp/czech republic) that should allow the user to see all host groups.

The reason is that when `Hostgroup.taxable_ids` is called `Organization.ignore?` does not realize that there it should look in all Organizations to see if any of them 'ignores' (has "all host groups" checked) the resource. The same thing happens with Locations.

The fix is to make `ignore?` aware the 'Organization.current == nil' means 'Any organization', not 'No organization'.