[MariaDB Packagers] MariaDB Galera Cluster 5.5.58 release prep

Prep work for the MariaDB Galera Cluster 5.5.58 release has begun. Expected release date is Tue, 25 Oct 2017. Draft release notes and changelog: - https://mariadb.com/kb/en/library/mgc-5558-rn/ - https://mariadb.com/kb/en/library/mgc-5558-cl/ As usual, the release notes and changelog are still in draft form at this time and they may be updated prior to release. Thanks. -- Daniel Bartholomew, MariaDB Release Manager MariaDB | http://mariadb.com