databases/mysql56-{server client}: Update to latest 5.6.37
This release contains
features:

• The mysql client now supports a --binary-as-hex option for binary data (Bug #25340722, Bug #84391)
• mysqlaccess now looks for its configuration file only in the SYSCONFDIR directory and /etc. (Bug #25043674)

And bugfixes:

• mysqld: failed to start the server if the --datadir option was specified with a relative path name. (Bug #25364806)
• InnoDB: The server allocated memory unnecessarily for an operation that rebuilt the table. (Bug #25573565, Bug #85043)
• mysqldump: could write database names in USE statements incorrectly. (Bug #25998635)

Reviewed by: mat (mentor)
Approved by: mat (mentor)
Sponsored by: Netzkommune GmbH
Differential Revision: https://reviews.freebsd.org/D11638