Description of problem:
If a host cannot be found in the candlepin database, attempting to delete this host will fail with an error similar to the following:

Katello::Resources::Candlepin::Consumer: 404 Resource Not Found {"displayMessage":"Consumer with id e7d9a1f4-51f7-4b9a-b92b-43f72ce371de could not be found.","requestUuid":"22fcfb9a-6e57-46ca-8e39-184ec57035c2"} (DELETE /candlepin/consumers/e7d9a1f4-51f7-4b9a-b92b-43f72ce371de) 

Katello::Resources::Candlepin::Consumer: 404 Resource Not Found {"displayMessage":"Consumer with id d346d3f2-a287-4e55-8a93-eec225495245 could not be found.","requestUuid":"614508bb-5b43-4ac4-9768-ad82a884dfbb"} (DELETE /candlepin/consumers/d346d3f2-a287-4e55-8a93-eec225495245)

Version-Release number of selected component (if applicable):
Satellite 6.3.1

How reproducible:

The customer is not sure how the host got into its current state. I was able to reproduce it by manually deleting candlepin records from the database.


Steps to Reproduce:
1. Register a content host to Satellite
2. Connect to the candlepin database and run queries to delete the consumer. Example:

delete from cp_consumer_facts where cp_consumer_id = '4028fcae632b664d01632cc5dffd0000';
delete from cp_ent_certificate where entitlement_id in (select id from  cp_entitlement where consumer_id = '4028fcae632b664d01632cc5dffd0000');
delete from cp_entitlement where consumer_id = '4028fcae632b664d01632cc5dffd0000';
delete from cp_installed_products where consumer_id = '4028fcae632b664d01632cc5dffd0000';
delete from cp_consumer where id = '4028fcae632b664d01632cc5dffd0000';

3. Attempt to delete the host via the web UI or hammer

Actual results:
Host is not deleted and an error is received

Expected results:
Host is deleted

Additional info:
We also tried using the following but it did not help:

# foreman-rake katello:clean_backend_objects COMMIT=true
# foreman-rake katello:reimport