Default to MariaDB for SLES 12

[cyberious]

No description provided.

[hunner]

I think merging #548 should handle this and every other case. Hardcoding providers is a 👎

[cyberious]

It doesn't handle it or the install, which is why it is failing, do we delay it it until @igalic can get finish or bite the bullet with this fix until we polish the other. SLES 12 has no options available except MariaDB, mysql is not available via zypper

[cyberious]

@hunner if you look closely at Igalic's this has nothing to do with the provider as such and about the packages to be installed. the Params that are in #548 do the same exact thing, just adding another operatingsystem check for SLES 12 same as exist in that PR for Redhat and others.