Add support for MySQL servers that require encrypted connections.

[scottmckenzie]

This PR allows connecting to MySQL servers that require encrypted connections (option require-secure-transport=ON).

To use:

• Set $dbsslca to the full path of a file that contains list of trusted SSL Certificate Authorities.
• Set $dbsslcapath to a directory that contains trusted SSL Certificate Authority certificate files.
• Set $dbsslverifycert to false to disable verification of the server SSL certificate.