Protect URI reingest from failure due to malformed XML

Protect URI reingest from failure due to malformed XML

In an ideal world, there would be no malformed XML. But our world is the
real world of libraries, and while the well_formed_xml() protects
against malformed XML in Evergreen 2.0 systems, in some cases bad XML
has been able to find its way into Evergreen systems in the past.

A single biblio.record_entry row containing malformed XML in the marc
column will prevent the call to reingest URIs from succeeding. By
limiting the set of records to those with well-formed XML, we can
increase the chance of the URI reingest succeeding at the cost of more
processing time.

Signed-off-by: Dan Scott <dscott@laurentian.ca>
Signed-off-by: Galen Charlton <gmc@esilibrary.com>