Add several insecure-related attributes

This change adds some attributes into the cookbook so
that they are configurable. They are mainly to configure
for glance_api_insecure and neutron_api_insecure in nova.conf.
It also makes neutron_url and neutron_admin_auth_url to be
prefixed with scheme(http or https).

Change-Id: If6d50a6963b47ee0983ecc71087414ab7c366623
Closes-Bug: #1381599