Upgrade of Red Hat Satellite 6 fails during a database migration

Issue

• Red Hat Satellite 6.7 upgrade fails with following error :

  Upgrade Step: migrate_foreman...
  /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
  API controllers newer than Apipie cache! Run apipie:cache rake task to regenerate cache.
  /opt/theforeman/tfm/root/usr/share/gems/gems/katello-3.7.0.59/app/models/katello/concerns/content_facet_host_extensions.rb:7: warning: already initialized constant Katello::Concerns::ContentFacetHostExtensions::ERRATA_STATUS_MAP
  /opt/theforeman/tfm/root/usr/share/gems/gems/katello-3.7.0.59/app/models/katello/concerns/content_facet_host_extensions.rb:7: warning: previous definition of ERRATA_STATUS_MAP was here
  /opt/theforeman/tfm/root/usr/share/gems/gems/katello-3.7.0.59/app/models/katello/concerns/content_facet_host_extensions.rb:14: warning: already initialized constant Katello::Concerns::ContentFacetHostExtensions::TRACE_STATUS_MAP
  /opt/theforeman/tfm/root/usr/share/gems/gems/katello-3.7.0.59/app/models/katello/concerns/content_facet_host_extensions.rb:14: warning: previous definition of TRACE_STATUS_MAP was here
  /opt/theforeman/tfm/root/usr/share/gems/gems/katello-3.7.0.59/app/models/katello/concerns/subscription_facet_host_extensions.rb:13: warning: already initialized constant Katello::Concerns::SubscriptionFacetHostExtensions::SUBSCRIPTION_STATUS_MAP
  /opt/theforeman/tfm/root/usr/share/gems/gems/katello-3.7.0.59/app/models/katello/concerns/subscription_facet_host_extensions.rb:13: warning: previous definition of SUBSCRIPTION_STATUS_MAP was here
  rake aborted!
  StandardError: An error has occurred, this and all later migrations canceled:
  PG::InternalError: ERROR:  right sibling's left-link doesn't match: block 6 links to 184 instead of expected 5 in index "index_audits_on_id"
  : UPDATE "audits" SET "auditable_type" = 'Host::Base' WHERE "audits"."auditable_type" = $1
  /opt/theforeman/tfm-ror51/root/usr/share/gems/gems/activerecord-5.1.6/lib /active_record/connection_adapters/postgresql_adapter.rb:616:in `async_exec'