Bug 35141: Prevent link_bibs_to_authorities from dying on invalid metadata

Bug 35141: Prevent link_bibs_to_authorities from dying on invalid metadata

When fetching the record we need to eval in case of exception

To test:
1 - Apply first patch
2 - perl misc/link_bibs_to_authorities.pl
3 - Note it dies on parser error at record 369
4 - Apply this patch
5 - perl misc/link_bibs_to_authorities.pl
6 - The process completes - with warning thrown on record 369

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>