Fix mysqli driver options

Some mysqli driver options have to be set before actually performing a database connect. `MYSQLI_OPT_LOCAL_INFILE` for example needs to be set before connect and cannot be changed afterwards. I encountered this issue today while trying to perform a `LOAD DATA local INFILE` statement with this driver. Setting the driver options before connect solved the issue.
I wanted to add a test for this but to be honest I have no idea how to test that the driver options are set before connect as both actions happen during construction of the mysqli connection instance.