Part of LP bug 963341 is about how the setting opac.fully_compressed_serial_holdings
breaks staff's ability to manage MFHD attached to serials records. This
commit unbreaks that by fetching the relevant MFHD regardless of that setting
but should not otherwise change user-visible behavior.
Signed-off-by: Mike Rylander <mrylander@gmail.com> Signed-off-by: Galen Charlton <gmc@esilibrary.com>