Free the MYSQL client handle after mysql_close to avoid a memory leak.
Free the MYSQL client handle after mysql_close to avoid a memory leak.

Resolves #700, #701, #702. Updates #663.
Thanks to @darix and @tenderlove for reporting and debugging.

tamird/mysql2,sodabrew/mysql2,brianmario/mysql2,jeremy/mysql2,brianmario/mysql2,kamipo/mysql2,brianmario/mysql2,yui-knk/mysql2,tamird/mysql2,kamipo/mysql2,jconroy77/mysql2,bigcartel/mysql2,sodabrew/mysql2,bigcartel/mysql2,bigcartel/mysql2,bigcartel/mysql2,jeremy/mysql2,tamird/mysql2,sodabrew/mysql2,kamipo/mysql2,yui-knk/mysql2,jeremy/mysql2,yui-knk/mysql2,tamird/mysql2,kamipo/mysql2,yui-knk/mysql2,jconroy77/mysql2,jconroy77/mysql2,jconroy77/mysql2