Bug 15741: Fix rounding in total fines calculations

 Bug 15741: Fix rounding in total fines calculations

C4::Members::GetMemberAccountRecords wrongly casts float to integer
It's common to use sprintf in Perl to do this job.

% perl -e 'print int(1000*64.60)."\n"';
64599
% perl -e 'print sprintf("%.0f", 1000*64.60)."\n"';
64600

Test plan:
1) Create manual invoice for 64.60 (or 1.14, 1.36, ...)
2) Try to pay it using "Pay amount" or "Pay selected" buttons

Signed-off-by: Sally Healey <sally.healey@cheshiresharedservices.gov.uk>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Brendan A Gallagher <brendan@bywatersolutions.com>