This branch enforces the use of generic MariaDB server paths for their
binaries and data rather than custom paths.
/usr/local/mariadb/columnstore is now only for columnstore with this
patch.
It should be noted that this removes the auto-mounting of external
MariaDB UM data storage for AWS.
This is also a fix for MCOL-3510 after buildbot changes are made.
Also... MCOL-3552 Use columnstore.cnf to load plugins
The ColumnStore plugins now load using a columnstore.cnf instead of a
SQL sequence to be more in-line with MariaDB's methods.
