Configure glance_api_insecure and glance_api_servers

This change adds some attributes into the cookbook so
that they are configurable. They are mainly to configure
for glance_api_insecure and make glance_api_servers to be
prefixed with scheme(http or https).

Change-Id: I79e04b47918fe1ec0b45472bd2cec9afa73d5897
Closes-Bug: #1383619