Description of problem:

Local custom yum repositories with Upstream Repository URL file:// is causing foreman-rake katello:upgrades:3.8:clear_checksum_type to fail:

# foreman-rake katello:upgrades:3.8:clear_checksum_type --trace
/usr/share/foreman/lib/foreman.rb:8: warning: already initialized constant Foreman::UUID_REGEXP
/usr/share/foreman/lib/foreman.rb:8: warning: previous definition of UUID_REGEXP was here
/usr/share/foreman/lib/core_extensions.rb:182: warning: already initialized constant ActiveSupport::MessageEncryptor::DEFAULT_CIPHER
/opt/theforeman/tfm-ror51/root/usr/share/gems/gems/activesupport-5.1.6/lib/active_support/message_encryptor.rb:22: warning: previous definition of DEFAULT_CIPHER was here
/usr/share/foreman/lib/tasks/repair_repos_62.rake:2: warning: already initialized constant PULP_IDS_FILE
/usr/share/foreman/lib/tasks/repair_repos.rake:2: warning: previous definition of PULP_IDS_FILE was here
** Invoke katello:upgrades:3.8:clear_checksum_type (first_time)
** Invoke environment (first_time)
** Execute environment
** Execute katello:upgrades:3.8:clear_checksum_type
rake aborted!
ActiveRecord::RecordInvalid: Validation failed: Download policy Cannot sync file:// repositories with On Demand or Background Download Policies
/opt/theforeman/tfm-ror51/root/usr/share/gems/gems/activerecord-5.1.6/lib/active_record/validations.rb:78:in `raise_validation_error'
/opt/theforeman/tfm-ror51/root/usr/share/gems/gems/activerecord-5.1.6/lib/active_record/validations.rb:50:in `save!'
...
...
...

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

Satellite 6.4.0

How reproducible: 100%


Steps to Reproduce:
1. Have a custom repository with Upstream URL repository pointing to file://
2. Try to upgrade to 6.4.0
3. It fails with above

Actual results:

katello:upgrades:3.8:clear_checksum_type is trying to forcefully set on Demand or Background download policy on locally hosted repos

Expected results:

katello:upgrades:3.8:clear_checksum_type will not try to change download policy on locally hosted yum repositories (Upstream Repository URL file://)