Description of problem:
There seems to be yet another race condition, which occurs during registering a host and creating an org (or possibly even an user) simultaneously.
Any other registration attempt after this error is unsuccessful (it seems to generate the same, already existing id)


It looks like this started occurring with 6.2.12-1

Version-Release number of selected component (if applicable):
6.2.12-1

Steps to Reproduce:
1. Start registering a host (using satellite hammer: `hammer host subscription register --content-view-id="372" --organization-id="305" --name="hXFzBtcMHyhUroM" --lifecycle-environment-id="298")`
2. create an organization just after the step #1 (before it finishes)

Actual results:
2017-08-25 19:41:41 7e368fba [app] [I] Started POST "/api/hosts/subscriptions" for 127.0.0.1 at 2017-08-25 19:41:41 -0400
2017-08-25 19:41:41 7e368fba [app] [I] Processing by Katello::Api::V2::HostSubscriptionsController#create as JSON
2017-08-25 19:41:41 7e368fba [app] [I]   Parameters: {"name"=>"PdUZAiadiJHKLuq", "facts"=>"[FILTERED]", "lifecycle_environment_id"=>423, "content_view_id"=>470, "api_version"=>"v2", "host_subscription"=>{"name"=>"PdUZAiadiJHKLuq", "facts"=>"[FILTERED]", "lifecycle_environment_id"=>423, "content_view_id"=>470}}
2017-08-25 19:41:41 7e368fba [app] [I] Authorized user admin(Admin User
2017-08-25 19:41:46 7e368fba [audit] [I] [pduzaiadijhkluq] deleted 0 (4.8ms)
2017-08-25 19:41:46 7e368fba [audit] [I] [pduzaiadijhkluq] updated 1 (21.7ms)
2017-08-25 19:41:46 7e368fba [audit] [I] [pduzaiadijhkluq] added 0 (2.4ms)
2017-08-25 19:41:46 7e368fba [app] [I] Import facts for 'pduzaiadijhkluq' completed. Added: 0, Updated: 1, Deleted 0 facts
2017-08-25 19:41:46 7e368fba [app] [I]   Rendered /opt/theforeman/tfm/root/usr/share/gems/gems/katello-3.0.0.151/app/views/katello/api/v2/hosts/show.json.rabl within katello/api/v2/layouts/resource (22.6ms)
2017-08-25 19:41:46 7e368fba [app] [I] Completed 200 OK in 4812ms (Views: 30.9ms | ActiveRecord: 99.3ms)
...
2017-08-25 19:41:56 b6baa7e4 [app] [I] Started POST "/api/hosts/subscriptions" for 127.0.0.1 at 2017-08-25 19:41:56 -0400
2017-08-25 19:41:56 b6baa7e4 [app] [I] Processing by Katello::Api::V2::HostSubscriptionsController#create as JSON
2017-08-25 19:41:56 b6baa7e4 [app] [I]   Parameters: {"name"=>"GgFnZCmReSviXca", "facts"=>"[FILTERED]", "lifecycle_environment_id"=>421, "content_view_id"=>468, "api_version"=>"v2", "host_subscription"=>{"name"=>"GgFnZCmReSviXca", "facts"=>"[FILTERED]", "lifecycle_environment_id"=>421, "content_view_id"=>468}}
2017-08-25 19:41:56 b6baa7e4 [app] [I] Authorized user admin(Admin User)
2017-08-25 19:41:58 b6baa7e4 [app] [E] ForemanTasks::TaskError: Task a45ef952-1fb3-4e59-96a8-b9ba4516c20d: ActiveRecord::RecordNotUnique: PG::Error: ERROR:  duplicate key value violates unique constraint "index_katello_subscription_facets_on_user_id"


Another occurrence:

2017-08-26 02:09:45 1a24ce39 [app] [I] Started POST "/api/hosts/subscriptions" for 127.0.0.1 at 2017-08-26 02:09:45 -0400
2017-08-26 02:09:46 1a24ce39 [app] [I] Processing by Katello::Api::V2::HostSubscriptionsController#create as JSON
2017-08-26 02:09:46 1a24ce39 [app] [I]   Parameters: {"name"=>"hXFzBtcMHyhUroM", "facts"=>"[FILTERED]", "lifecycle_environment_id"=>298, "content_view_id"=>372, "api_version"=>"v2", "host_subscription"=>{"name"=>"hXFzBtcMHyhUroM", "facts" 
2017-08-26 02:09:46 1a24ce39 [app] [I] Authorized user admin(Admin User)
...
2017-08-26 02:09:48 f7726c0e [app] [I] Started POST "/katello/api/v2/organizations" for 10.8.0.99 at 2017-08-26 02:09:48 -0400
2017-08-26 02:09:48 f7726c0e [app] [I] Processing by Katello::Api::V2::OrganizationsController#create as */* 
2017-08-26 02:09:48 f7726c0e [app] [I]   Parameters: {"name"=>"hdpYSCNhg", "api_version"=>"v2", "organization"=>{"name"=>"hdpYSCNhg"}}
2017-08-26 02:09:48 f7726c0e [app] [I] Authorized user admin(Admin User)
2017-08-26 02:09:49  [foreman-tasks/action] [E] PG::Error: ERROR:  duplicate key value violates unique constraint "index_katello_subscription_facets_on_user_id"
 | DETAIL:  Key (user_id)=(3) already exists.
...
2017-08-26 02:09:49 1a24ce39 [app] [E] ForemanTasks::TaskError: Task 825b9c29-648e-49b9-ba5c-0c6f8b6c3fad: ActiveRecord::RecordNotUnique: PG::Error: ERROR:  duplicate key value violates unique constraint "index_katello_subscription_facets
 | DETAIL:  Key (user_id)=(3) already exists.


Expected results:
no conflict, the tasks should be atomic

Additional info: