* CloudManagement.execute_on_cloud is abstract now.
* CloudManagement.get_service is not abstract now and
should be the same for all cloud management drivers.
* Moved basic methods of FuelNodeCollection to NodeCollection.
* Moved FuelService to common/service.py and
renamed to ServiceAsProcess.
* Cleaned up devstack driver:
- DevStackNode now uses the same methods as FuelNodeCollection.
- ServiceAsProcess is used for devstack services.
- Added execute_on_cloud method to allow using common services.
* Added common Host class.
Change-Id: I50334db300098c5aaf410a2b28cdc3c72ebd065e
2ddabc2c18