Ticket 7662 - db2index not properly evalauating arguments
Description: Fix a regression where the argument count gets adjusted
before it is checked for errors. The fix is to copy the
number before we shift the arguments, and use that copy
for the usage check.
https://pagure.io/389-ds-base/issue/47662
Reviewed by: firstyear(Thanks!)
(cherry picked from commit 46011e24580fcee2f438506f91b9fc119306defc)