(maint) Disable SSLv3 in example activemq configurations

As discussed in more depth by Mike Stankhe's blog post, in order to mitigate
the impact of the POODLE vulnerability we should not enable SSLv3 for ssl-based
transportConnector.

With this commit we update the example activemq configurations and related
documents to disable SSLv3.

https://puppetlabs.com/blog/impact-assessment-sslv3-vulnerability-poodle-attack