LP#1773479 Show Located URIs in browse

LP#1773479 Show Located URIs in browse

Located URIs depend upon bib-level visibility, as there are no copies
to work with.  The browse code, however, was joining in the copy
visibility table as if it would always have at least one row per bib,
but in the case of located URIs, it does not.

Let's change it to a LEFT JOIN to allow the bib row to show up, at
which point the existing bib visibility check can do its job.

Signed-off-by: Dan Wells <dbw2@calvin.edu>
Signed-off-by: Mike Rylander <mrylander@gmail.com>