Host registration using bootstrap script fails with [0 element in array for search key 'title="RHEL 5"' in API '/api/v2/operatingsystems'.] in Red Hat Satellite 6

Issue

• While registering the host to Red Hat Satellite 6 using bootstrap method getting Operating System error as follows:

      # ./bootstrap.py --login=satadmin --password=satpassword --server=satellite.example.com --location="ABC" --organization="RedHat" --activationkey="RHEL AK" --operatingsystem="RHEL 5" --hostgroup="RHELHG"
      Foreman Bootstrap Script
      This script is designed to register new systems or to migrate an existing system to a Foreman server with Katello
      .
      .
      .
      [RUNNING], [2020-07-14 18:45:17], [rpm -Uvh http://satellite.example.com/pub/katello-ca-consumer-latest.noarch.rpm]
      Retrieving http://satellite.example.com/pub/katello-ca-consumer-latest.noarch.rpm
      Preparing... ##################################################
      katello-ca-consumer-satellite##################################################
      [SUCCESS], [2020-07-14 18:45:18], [rpm -Uvh http://satellite.example.com/pub/katello-ca-consumer-latest.noarch.rpm], completed successfully.
      [NOTIFICATION], [2020-07-14 18:45:18], [Writing FQDN katello-fact]
      [ERROR], [2020-07-14 18:45:19], EXITING: [0 element in array for search key 'title="RHEL 5"' in API '/api/v2/operatingsystems'. Please note that all searches are case-sensitive.] failed to execute properly.
      [ERROR], [2020-07-14 18:45:19], EXITING: [Please also ensure that the user has permissions to view the searched objects. Fatal error.] failed to execute properly.