LP#1374551: Create index on money.billing.voider to speed user merge.

Signed-off-by: Chris Sharp <csharp@georgialibraries.org>
Signed-off-by: Ben Shum <bshum@biblio.org>
LP#1374551: Stamping upgrade script for new index on money.billing.voider

Signed-off-by: Ben Shum <bshum@biblio.org>