[Koha] Bug with link_bibs_to_authorities introduced in 3.8.7

Patch 8823 has introduce a bug (tracked in http://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=9149) where C4/Biblio.pm calls a non-existent subroutine: GetAuthorizedHeading. This breaks bin/ link_bibs_to_authorities.pl. I have informed the author of the patch.