invoice_subsystem: fix inaccuracies
invoice_subsystem: fix inaccuracies

We don't create an empty invoice_payment row anymore when
the built-in __INVOICE_PAYMENT_CONTROL_PLUGIN__ aborts the payment.

Signed-off-by: Pierre-Alexandre Meyer <ff019a5748a52b5641624af88a54a2f0e46a9fb5@mouraf.org>

killbill/killbill-docs,killbill/killbill-docs