Bug 26270: Fix ThingISBN after a change in behaviour

Bug 26270: Fix ThingISBN after a change in behaviour

This is just a guess! One of our tests is failing since today and we
don't modify anything in this area.
My guess is that the service is now returning the normalized version of
the ISBN

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Aleisha Amohia <aleishaamohia@hotmail.com>
(cherry picked from commit 7a34b88885c13a89cd713bb76eadef11472c1960)
Signed-off-by: Victor Grousset/tuxayo <victor@tuxayo.net>