LP 1350345: marc_export blows up on bad records.

Add some eval blocks around calls to MARC::Record->as_usmarc and
MARC::Record->as_xml_record to trap errors in bibliograpic and
authority records.

If MARC::Record reports an error, print the record id and the
error message and continue the export.

Signed-off-by: Jason Stephenson <jstephenson@mvlc.org>
Signed-off-by: Ben Shum <bshum@biblio.org>