LP#1756912: restore display of copy counts for preferred library

LP#1756912: restore display of copy counts for preferred library

This patch fixes a regression introduced by the patches for bug 1698206
and restores the display of copy counts for the preferred library (when set)
on the public catalog results and record details pages.

To test
-------
[1] Log into the public catalog as a user and set a preferred library.
[2] Perform a catalog search at a system that is other than the
    preferred library set in step 1. Repeat the search with
    "Groups Formats and Editions" checked.
[3] Note that in both cases, the copy counts displayed in search results and
    the record details pages do not include a line for the preferred
    library.
[4] Apply the patch and repeat step 2. This time, the preferred library
    count should be included in the display.

The substance of this patch (with the exception of the pgTAP tests)
follows an approach suggested by Bob Wicksall <bwicksall@pls-net.org>

Signed-off-by: Galen Charlton <gmc@equinoxinitiative.org>