Skip validating cert :(

This seems to be necessary to get our jenkins-workers building again. I don't entirely understand since this worked a month ago and we were running it with ansible 1.7.1 anyway.

@fredsmith I don't suppose you could suggest a different solution? 

CC @singingwolfboy 
An alternative would be to use CURL instead of get_url which seems to be validating certs correctly.  Take a look at what @fredsmith did for the get_url calls in common.