install: change default DB driver to 'mysql' (see issue #765)
install: change default DB driver to 'mysql' (see issue #765)

The current version of CodeIgniter's 'mysqli' driver doesn't support the
backup() method.

kelaskakap/cms-api-unggun,PeterRock/Ci-Bonfire3,kelaskakap/cms-api-unggun,PeterRock/Ci-Bonfire3,kelaskakap/cms-api-unggun,PeterRock/Ci-Bonfire3