Deltacloud - adds maps openstack 'regions' to deltacloud realms - DTACLOUD-443

https://issues.apache.org/jira/browse/DTACLOUD-443

API-Change: Added the 'resource_types' attribute to Realm model
Deltacloud - adds EC2 driver import key functionality - DTACLOUD-438
(+updated gemspec for aws 2.7.0 required here)

https://issues.apache.org/jira/browse/DTACLOUD-438