Bug 32445: (follow-up) Fix availability display on opac-course-details

Bug 32445: (follow-up) Fix availability display on opac-course-details

This is reverting a change made by
  commit 52b5cdf79b53eb29173e92a7dfe0f76df135e7d9
  Bug 19532: Recalls on OPAC

Is it correct? I let a comment on bug 19532 comment 928 to ask for
clarification.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
(cherry picked from commit 217ccf2eaebe847937e0961b307382758caf6338)
Signed-off-by: Jacob O'Mara <jacob.omara@ptfs-europe.com>