so that a user can force a new media set, e.g. if he uses the
allocation policy 'continue', but wants to manually start a new
media-set.
Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
if the reader thread is already gone here, we panic here, resulting in
a nondescript error message, so simply ignore/warn in that case and
return gracefully
Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>