Normalize records imported from Z39.50 servers.

Normalize records imported from Z39.50 servers.

Some Z39.50 server may use the MARC-8 encoding, which uses separated
diacritics. By forcing a normalization, all imported records will have
combined diacritics.

Records with separated diacritics might not show up in Zebra searches if
the search terms use accented characters.

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
http://bugs.koha-community.org/show_bug.cgi?id=8610
Signed-off-by: Paul Poulain <paul.poulain@biblibre.com>
checked it still works after the patch with UNIMARC and BNF server (that
provide utf-8 records)