Bug 10201 [Follow-up] Old OPAC patron update system should be removed

Bug 10201 [Follow-up] Old OPAC patron update system should be removed

The previous patch missed removal of one template, kohaerror.tt, which
was used only by opac-userupdate.pl. This patch removes it.

To test, apply the patch and search Koha source files for references to
kohaerror. There should be none.

Signed-off-by: Mirko Tietgen <mirko@abunchofthings.net>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
All tests and QA script pass. Updating the German po files
with this patch applied no new strings appeared.
Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>
(cherry picked from commit 8aa2bb150ae384d4195bdcf178e82f495ede6a1b)

Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>