Add back --insecure option to CURL debug

This was added in review: https://review.openstack.org/#/c/53500 but
lost in the conversion to using session. Add it back again.

Change-Id: Ia063eb018d3a7da706a02d60df63bfa1be21d147
Related-Bug: #1249891
Merge "Add back --insecure option to CURL debug"