Properly create tenant default group for population

When creating a tenant, if there are already groups in the database,
it would assign a random group.
This would manifest by having a seemingly random group assigned to newly
discovered VMs/Hosts. There can then be privilege issues as the admins
possibly don't have access to the group.

This only happens for customers who had a database before tenancy
was introduced in 2015. It incorrectly assigned during the migration
process in 20151021174140_assign_tenant_default_group

The fix: it will now only assign a tenant group.

https://bugzilla.redhat.com/show_bug.cgi?id=1625788

I'm also adding a migration to automatically fix customer's databases
Since the issue was introduced in a migration in the first place.

app/models/miq_group.rb

@@ -229,9 +229,11 @@ def self.create_tenant_group(tenant)
 
     create_with(
       :description         => "Tenant #{tenant_full_name} access",
-      :group_type          => TENANT_GROUP,
       :default_tenant_role => MiqUserRole.default_tenant_role
-    ).find_or_create_by!(:tenant_id => tenant.id)
+    ).find_or_create_by!(
+      :group_type          => TENANT_GROUP,
+      :tenant_id           => tenant.id,
+    )
   end
 
   def self.sort_by_desc

spec/models/tenant_spec.rb

@@ -830,4 +830,22 @@
       expect(sub_tenant.parent_id = tenant.id).to eq(tenant.id)
     end
   end
+
+  describe "#create" do
+    it "properly creates a default group" do
+      # create a tenant, but one that doesn't have a default_miq_group
+      # this is only possibly during an upgrade
+      tenant.save!
+      tenant.default_miq_group.delete
+      tenant.update_attribute(:default_miq_group_id, nil)
+      # lets make sure the tenant doesn't get assigned this user created group (the bug)
+      false_group = FactoryGirl.create(:miq_group, :tenant_id => tenant.id)
+
+      # 20151021174140_assign_tenant_default_group.rb
+      tenant.send(:create_tenant_group)
+
+      expect(tenant.default_miq_group).not_to eq(false_group)
+      expect(tenant.default_miq_group).to be_tenant_group
+    end
+  end
 end