LP#1488655: fix MR remapping upon fingerprint change
This patch ensures that if the fingerprint of a bib changes, the
bib will be moved to a new metarecord as opposed to ending up
as a member of more than one metarecord.
To test
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[1] Note the metarecord that a bib belongs to.
[2] Change the bib so that its fingerprint changes -- with stock
cbf settings, editing the 245$a should suffice.
[3] Note that it is now a component of two metarecords.
[4] Apply the patch.
[5] Repeat step 2 or force a reingest. The bib should now be part
of exactly one metarecord.
LP#1488655: regression test for metarecord remapping
This patch contains pgTAP tests for verifying that when
the fingerprint of a bib is changed, it remains part of
exactly one metarecord (as opposed to being part of both
its old and new MRs).
