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: I2b73a532deb8782c2c0bb05070b727e9edc6e9d8
Co-written-by: Riccardo Pittau <elfosardo@gmail.com>
Signed-off-by: Sean McGinnis <sean.mcginnis@gmail.com>