Bug 13408: Tell librarians they may continue scanning while checkouts table is loading

Bug 13408: Tell librarians they may continue scanning while checkouts table is loading

Some librarians do not realize they can continue scanning items even if
the checkouts table has not loaded. We should have Koha tell them
explicitly that they may continue scanning barcodes.

Test Plan:
1) Apply this patch
2) Load the checkouts table on circulation.pl, note the loading message is now
   Loading... you may continue scanning.
3) Load the checkouts table on moremember.pl, note the loading message is still
   Loading...

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
This one works too!

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>
(cherry picked from commit 28513edb943c255b191c94e0fbc0fe14368e6985)
Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>