Make test-setup.sh compatible with mysql8

Starting from mysql version 8 it's not possible to create a user
implictly when using GRANT.

This patch makes the behavior compatible with that.

Change-Id: Ia13402213bc82027e3d658918a22003be26576d6
Co-Authored-By: Sean McGinnis <[email protected]>
(cherry picked from commit ae22b23)

Author: priteau