Bug 24786: Update borroaccount to use session register
This patch adds handling to allow for the use of the session cash
register by default if it has been set, otherwise it defaults to '--
None --' and requires the end user to select the register to proceed
with the refund or payout action.
Signed-off-by: Andrew Fuerste-Henry <andrew@bywatersolutions.com> Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de> Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>