LP1752356 Offline expired patrons download date additions

LP1752356 Offline expired patrons download date additions

Modify wording to clarify the date displayed is that of the block list
download and not necessarily the date the patron was flagged expired.

Avoid console errors when the file download date is not known -- edge
case where the code is updated but the block list was not updated in the
meantime.

Clean up some debug logging.

Signed-off-by: Bill Erickson <berickxx@gmail.com>
Signed-off-by: Terran McCanna <tmccanna@georgialibraries.org>
Signed-off-by: Jason Boyer <jboyer@equinoxOLI.org>