Update docs to include `secureProtocol` parameter for `tls` and `https` modules

There is an issue with some servers that cause SSL requests using the default SSL method to fail, for example:

http://webcache.googleusercontent.com/search?q=cache:_tRN2R7Awr0J:carnivore.it/2011/10/07/error_14077458_ssl_routines_ssl23_get_server_hello_reason_1112&hl=en&gl=us&strip=1

http://curl.haxx.se/mail/archive-2010-03/0069.html

Node provides an undocumented `secureProtocol` parameter to fix this, the code for which is here:

https://github.com/joyent/node/blob/179784e31e72fcdd0a2b1a596f7aebb43dc87913/lib/crypto.js#L60

This pull request adds documentation for that parameter to the `tls` and `https` modules so that it is easier to find for others. There is also a pull request open with Needle that is blocked on the parameter being properly documented at https://github.com/tomas/needle/pull/24#issuecomment-17956374

Thanks!