Description of problem:

Unable to run a rex job when a provisioned host is deleted and created again with same IP address

How reproducible:

100%

Is this issue a regression from an earlier version:

No

Steps to Reproduce:

1. Provision a host
2. Run a rex job (set Connect by IP to Yes)
3. Delete the host and create a new host(give same IP to the host as of the first provisioned host)
4. Try running a rex job again

Actual behavior:
The rex job fails on the host.
The job error is `Offending ED25519 key in /usr/share/foreman-proxy/.ssh/known_hosts:1`

Expected behavior:
The rex job should pass

Business Impact / Additional info: