add glance image properties support for magnum.

From this review - https://review.openstack.org/#/c/165346/

As discussed in the meeting, we will retrieve os_type from glance image properties, not to store at baymodel side. we need to update os_type for the image we create in glace for magnum. For this implementation, need to call glance image properties api to pull os_type property from the glacen image. According to the os_type, we will have to select appropriate template for coreos etc. I am removing cluster_type from current implementation.

Digambar Mar 27 9:34 AM
Patch Set 6:
I think os_distro image property option is best instead of using os_type. os_distros refers to debian, fedora, ubuntu etc. but os_type refers only windows or linux. In our case, os_distro image property is required. See this - http://docs.openstack.org/cli-reference/content/chapter_cli-glance-property.html

Digambar Mar 27 10:24 AM
Patch Set 6:
https://wiki.openstack.org/wiki/Glance-common-image-properties#Property:_os_distro