Updated openstack/openstack
Project: openstack/heat  91fddd5c45852b6221e9008e2a728ee5bfa64798

Instructions on image creation for SoftwareConfig.

Instructions on creating images that can be used for SoftwareConfig and
SoftwareDeployment are added.

Change-Id: If4bc6197ca38d73378ada6a6b32e47a658d88fc5