The 'unsubscribe' command of 'subscription-manager' was deprecated
already in subscription-manager 1.11.3, shipped with RHEL 5.11.
As it was removed in subscription-manager 1.29.x, unsubscribing from
pools was thus broken.
The simple fix is to call the proper command, 'remove'.
(cherry picked from commit a45b90e93f)
Co-authored-by: Pino Toscano <ptoscano@redhat.com>
