LP20474587 Fix copy stat cat fleshing in SuperCat

LP20474587 Fix copy stat cat fleshing in SuperCat

Fix an internal server error caused by lack of fleshed stat cats when
retrieving copies or call numbers via SuperCat.

To reproduce this bug visit the locations below on an Evergreen
installation where copy stat cats are in use.  Be sure to pick a copy
id or call number with copies that have stat cats assigned.

/opac/extras/supercat/retrieve/marcxml/acn/<call number id>

or

/opac/extras/supercat/retrieve/marcxml/acp/<copy_id>

Before this patch, visiting either should produce an internal server
error.

Afater applying this patch and reinstalling Evergreen, you should get
the expected ouput, including any OPAC visible stat cat entries.

Release-note: Fix an Apache internal server error in SuperCat when retrieving copies or call numbers with statistical categories.

Signed-off-by: Jason Stephenson <jason@sigio.com>
Signed-off-by: Galen Charlton <gmc@equinoxOLI.org>