This went EOL in December 2018. We don't need this logic. A release note
is included, even though this isn't really needed (we don't formalize
our support for different MySQL versions anywhere, and are mostly
dependent on what SQLAlchemy/oslo.db support)
Change-Id: Ie78d6e7612d84c712c8dc6fb5effc2b8bd5b4b22
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>