Bug 5264 (Retain additional bibliographic subfields when merging authorities) [for...

Bug 5264 (Retain additional bibliographic subfields when merging authorities) [for master only]

The current code in AuthoritiesMarc.pm rewrites all subfields from the report
tag in the authority record to fields in related bibliographic records when
merging authorities. Additional subfields in the biblio records (e.g. relator
code or term) are lost in the process.

This patch retains the original algorithm but restores the additional subfields
from the original biblio record when rewriting the linked marc fields.

The problem also exists in 3.0. Two separate patches have been submitted.

Signed-off-by: Galen Charlton <gmcharlt@gmail.com>