Bug 18083: Don't show 'library' selection on popular titles page for single-branch...

Bug 18083: Don't show 'library' selection on popular titles page for single-branch libraries

This patch hides the search filter labelled "From" that offers you to
select a library branch which is located on the 'popular titles' page on the OPAC. It is hidden when the library only has one branchas it would be unneccessary to have an option for other branches when there is only one.

Test Plan:
1) Make sure you have a single-branch library
2) Make sure OPACTopIssue is allowed in the OPAC preferences
3) In the OPAC, got to 'Most Popular' page
4) Check that there is no "From" filter in the refine search
5) Create a new branch so that you have more than one branch
6) Check that there is a "From" filter in the refine search on the Most Popular page.

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Amended white space on second change.

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>