SSL sockets may leak when keepalive is enabled

[alexpenev-s]

issue is in: lib/_http_agent.js
The issue is reproducible whenever the ca property is set globally in the agent and an https request is made with https.request(ops) where ops does not have the property ca

_http_agent.js @ Agent.prototype.createSocket
the options are extended with the global options object which contains ca. In getName ca is used in the name generation of the hash.

however _http_agent.js @ Agent.prototype.addRequest
The options (passed from the call https.request(ops) which don't have the property ca) are used to get a hashtag which is now different. The socket leaks and is closed when the timeout hits. Meanwhile a new socket is created for the request.

[benjamingr]

It's worth mentioning that this happens because getName is overridden in prototypical inheritance in `https://github.com/nodejs/node/blob/master/lib/https.js#L114 - _http_agent is not aware of the ca property.

[benjamingr]

Nice spotting and nice fix. Worth mentioning that the only place that addRequest uses options except in getName is when it calls createSocket itself - so this is a backwards compatibly.

Would you be willing to make a pull request of your branch against node @saperal ?

[alexpenev-s]

Done #5713