WL#8313: Set ROW based binary log format by default

This work changes the default of binlog-format to "ROW" (was: STATEMENT). 

Row format provides safe logging in all cases, and allows for improved InnoDB
locking semantics. 

See also:
http://www.tocker.ca/2015/01/14/proposal-to-change-replication-and-innodb-
settings-in-mysql-5-7.html

In response to feedback, we have decided to not change transaction_isolation at 
this point in time.