Bug 29757: (QA follow-up) POD fixes

Bug 29757: (QA follow-up) POD fixes

This patch adds POD, fixes the existing one in the file, and also
renames reversable => reversible as required by the QA scripts.

If this name change is problematic, I can revert it and resubmit my
follow-up.

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>