Fixes #37600 - ignore missing content on RH repo deletion

[ianballou]

What are the changes introduced in this pull request?

If the Candlepin SetContent action is trying to work with Content that don't exist, move on instead of erroring out with a 404.

Considerations taken when implementing this change?

I'm still not 100% certain if any action needs to be taken to remove the references to the Content that are missing in Candlepin.

In the case of my reproducer system, it seems like the deleted repository left behind an empty Red Hat product. I'm not sure how much better we can recover from that situation given that there is already some data corruption required to hit this issue.

Never mind this, the Product did disappear after all.

What are the testing steps for this pull request?

1. Create an environment with some Red Hat repositories that refer to content that does not exist in Candlepin
   a) I tested this with a reproducer machine, but to create your own reproducer it's likely that the Candlepin DB will need to be modified.
2. Apply the patch
3. Delete the repository and see that it completes successfully

[chris1984]

ACK, works well. Deleted the troublesome repos and it worked fine:

[root@rhvstlp1 certs_temp]# hammer repository destroy --id 1458 --organization-id 1
Repository deleted.
[root@rhvstlp1 certs_temp]# hammer repository destroy --id 1459 --organization-id 1
Repository deleted.

Then ran a script to delete repo id's from 1-2000 and that worked without any issues:

Deleting repo 17
Could not delete the Repository:
  Could not find repository resource with id 17. Potential missing permissions: destroy_products
Deleting repo 18
Repository deleted.
Deleting repo 19
Repository deleted.
Deleting repo 20
Deleting repo 1998
Could not delete the Repository:
  Could not find repository resource with id 1998. Potential missing permissions: destroy_products
Deleting repo 1999
Could not delete the Repository:
  Could not find repository resource with id 1999. Potential missing permissions: destroy_products
Deleting repo 2000
Could not delete the Repository:
  Could not find repository resource with id 2000. Potential missing permissions: destroy_products