Bug 14106: patch existing zebra configs with new modulePath

Bug 14106: patch existing zebra configs with new modulePath

This patches the zebra configuration of existing Koha installations so
that their modulePath will work on newer Debian (and presumably Ubuntu)
releases.

Testing:
* Install a package built with this patch onto a system with instances
  created by an older Koha version.
* Check that the files in /etc/koha/sites/*/zebra-*.cfg have the new
  modulePath: directive rather than the old one.

Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>