OAK-1266 - use 767 byte key for all databases (removing the MariaDB special case)

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1625926 13f79535-47bb-0310-9956-ffa450edef68
fix misleading log message

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1625927 13f79535-47bb-0310-9956-ffa450edef68