cmapi: Active nodes should not be removable

Build tested: 1.5.4-1 (Drone #587), cmapi (Drone #251)

With a 3-node cluster up and running and data spread over on all three local dbroots, I was able to remove a node (PM3) along with its dbroot.

A query on existing table returned an error.

MariaDB [tpch102]> select count from lineitem;
ERROR 1815 (HY000): Internal error: IDB-2039: Data file does not exist, please contact your system administrator for more information.

Active node and data should not be easily removed.