when --master-data is used

When using the --master-data option with mysqldump, mysqldump uses 
a FLUSH TABLES command.  However, this statement got replicated to 
the slave(s), which caused the slave(s) to block unnecessarily while
the FLUSH tables command completed.

Now, if the master-data option is set to one of the two "on" modes,
then use the "LOCAL" qualifier to ensure that it's not replicated.