Allow tls skip verify option

[EinAeffchen]

I am currently in a situation where I have to create an ssh tunnel to deploy eggs via the scrapyd client, which causes me to deploy through localhost and in turn leads to this error:

Deploy failed: <urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: self-signed certificate (_ssl.c:997)>

It would be great if I could just set tls_skip_verify in the scrapy.cfg and deploy anyways.

[jpmckinney]

Can you show the full stack trace?

[EinAeffchen]

I actually already build a solution to add more keys to the scrapy.cfg to bypass tls verification for tunneling through ssh. Because of that I can't recreate the stack trace anymore, but that was basically all the error I got anyways.
Just try to tunnel via ssh to your scrapyd server with ssl active and you will get the certificate error :)

As soon as I figure out how, I can submit a pull request for this issue.