Upgrade to Red Hat Satellite 6.9 fails in "Executing: katello-certs-check" step while custom SSL certificates are in use

Issue

• Upgrade to Red Hat Satellite 6.9 fails with the following issue.

  Checking for use of shortname as CN
  [FAIL]
  
  The satellite.crt is using a shortname for Common Name (CN) and cannot be used with Red Hat Satellite.
  
  
  [OK]
  
  katello-certs-check -c "/root/satellite.crt" -k "/root/satellite.key" -b "/etc/pki/tls/certs/mwam-ca.crt" failed! Check the output for error!
  2021-04-23 22:10:50 [ERROR ] [root] katello-certs-check -c "/root/satellite.crt" -k "/root/satellite.key" -b "/etc/pki/tls/certs/mwam-ca.crt" failed! Check the output for error!
                                    [FAIL]
  Failed executing LANG=en_US.utf-8 satellite-installer  --disable-system-checks, exit status 1
  ...
  Scenario [Migration scripts to Satellite 6.9] failed.
  
  The following steps ended up in failing state:
  
   [installer-upgrade]
  
  Resolve the failed steps and rerun
  the command. In case the failures are false positives,
  use --whitelist="installer-upgrade"