To provide a crash-safe slave, we had to change the engine used by the
tables slave_master_info, slave_relay_log_info and slave_worker_info
from MyISAM to Innodb. However, this additional step was causing 
confusion as simply storing replication meta-information into tables
was supposed to be safe. 
       
We had decided to use MyISAM to create the aforementioned tables to 
keep compatibility with system tables which also use MyISAM. 
       
To avoid any sort of confusion, we use now Innodb to create the tables: 
slave_master_info, slave_relay_log_info and slave_worker_info.