Allow setting options in designate section to specify if want
to skip SSL cert check. This makes it possible to work with HTTPS
based endpoints, the default behavior of keystoneclient is to always
set verify=True however in current code, one cannot either provide
a valid CA cert or skip the verification.
DocImpact: Introduce two additional options for `[designate]` section
in neutron.conf
CONF.designate.insecure to allow insecure connections over SSL.
CONF.designate.ca_cert for a valid cert when connecting over SSL
Change-Id: Ic371cc11d783618c38ee40a18206b0c2a197bb3e
Closes-Bug: #1588067