(#19151) Force puppet webrick server to SSLv3

Without this patch the SSL server used by Puppet will automatically
negotiate and communicate with SSLv2 clients.  This is a problem because
SSLv2 is known to be insecure and vulnerable to attack.  This patch
addresses the problem by forcing the HTTP Webrick server to use SSLv3
only.

This patch affects the Puppet agent SSL server on port 8139 and enabled
using the `--listen` option.  The patch also affects the Puppet master
SSL server running on port 8140 when run using the Webrick HTTP server.
It does not affect alternate HTTP SSL servers, such as the one shipped
with Puppet Enterprise.