LP#1751126: Make print holds shelf list aware of clear mode.

LP#1751126: Make print holds shelf list aware of clear mode.

We change the Print Full List button on the holds shelf view to be
aware of whether clear mode is active.  If clear mode is active, then
the list of holds to clear is printed.  If not, then the full holds
shelf list is printed.

This commit does not change the label of the print full list button.

Signed-off-by: Jason Stephenson <jason@sigio.com>
Signed-off-by: Dawn Dale <ddale@georgialibraries.org>
Signed-off-by: Galen Charlton <gmc@equinoxinitiative.org>