Expose more TLS socket options, enable them by default

[michaelklishin]

Proposed Changes

This adds support for a several more TLS socket options to ensure
that the recommendations/setup from http://www.rabbitmq.com/ssl.html#tls-evaluation-tools is
possible to achieve with this cookbook.

Types of Changes

• Bug fix (non-breaking change which fixes issue Support additional ssl_options for security #240)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation (correction or otherwise)
• Cosmetics (whitespace, appearance)

Checklist

• I have read the CONTRIBUTING.md document
• I have signed the CA (see https://cla.pivotal.io/sign/rabbitmq)
• All tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)
• Any dependent changes have been merged and published in related repositories

Further Comments

Closes #240.

[lukebakken]

rake spec passes, changes look good to me 👍