Bug 15572: TransformHtmlToMarc - rewrite the loop

Bug 15572: TransformHtmlToMarc - rewrite the loop

This rewrites the while loop into a for loop, so $i still gets
incremented when we call next

Signed-off-by: Frédéric Demians <f.demians@tamil.fr>
  Make sense. Add readability. Infinite loop no more possible.

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Jesse Weaver <jweaver@bywatersolutions.com>
(cherry picked from commit 1eab5c199d21a622abde7e47ca248d80e882ca46)
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>