shared cmmi TODO: mroonga and mariadb are not isolated

mroonga installs plugin .so files in mariadb directory, violating the
isolation of parts principle.

component/mariadb/buildout.cfg

@@ -89,6 +89,7 @@ recipe = slapos.recipe.cmmi
 shared = true
 url = http://packages.groonga.org/source/mroonga/mroonga-8.00.tar.gz
 md5sum = 8b906705be5fc14785207ca6752b96e9
+# TODO cmmi-cache: check this section, shouldn't we install another separate mariadb for this ?
 pre-configure = set -e
   rm -rf fake_mariadb_source
   mkdir -p fake_mariadb_source