Two new features for Galera
* Write a warning to error log if Galera replicates table with storage engine not supported by Galera (at the moment only InnoDB is supported
** Warning is pushed to client also
** MyISAM is allowed if wsrep_replicate_myisam=ON
* Write a warning to error log if Galera replicates table with no primary key
** Warning is pushed to client also
** MyISAM is allowed if wsrep_relicate_myisam=ON
* In both cases apply flood control if > 10 same warning is writen to error log
(requires log_warnings > 1), flood control will suppress warnings for 300 seconds