eucalytpus: rebase to cloud_aws for Eucalyptus 3.3.0 support

Eucalyptus 3.3.0 supports resource tagging, so the Eucalyptus provider
can now re-use most of the AWS EC2 provider logic.
eucalyptus: re-use InstanceStarter from cloud_aws
Merge remote-tracking branch 'hnousiainen/euca-3.3.0'