service can be given as parameter to stacky/hosts to get specific results
Merge pull request #222 from anujm/instance_flavor_id_support

Added verification for instance_flavor_id field
Merge pull request #227 from manalilatkar/stacky_hosts

stacky/hosts modification according to service input
Added south datamigration to populate instance_flavor_id
in InstanceUsage, InstanceExists and InstanceReconcile
using instance_type_id-to-instance_flavor_id csv mapping