Bug 6488 - followup - fixes issue with bibs with no items and serials being suppressed

Bug 6488 - followup - fixes issue with bibs with no items and serials being suppressed

To test:

* create a bib with no items
* update your index
	serial records and your new bib with no items should be displayed.
* add something to the OPACHiddenItems syspref (I like itype: [BK] from the test data)
*** test both ways, with something in there and with the syspref empty.
* add an item to your new bib that would be suppressed
* update your index
* search for the bib
	The item should not show
* change the item into a state where it would no longer be suppressed
* update your index
* search for the bib
	The item should show in the opac
* just for fun, delete your item
* update your index
* Search for the bib - it should still display.

I tested on MARC21 - please test UNIMARC as well.

Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>