Do not verify stagecraft certificate

We do not have the correct certificate for stagecraft available in
production. There is a story to fix this.

This change prevents requests from verifying the certificate. This is
safe enough because all the requests are within our network and we're
using dnsmasq for dns.
Change test to show requests sent without verify flag
Merge pull request #259 from alphagov/do-not-verify-stagcraft-host

Do not verify stagecraft certificate