[google] Implement operation model

Check that server and disk destroy operation starts successfully
Implement get and delete requests
Handle 204 responses without body
Return excon response with same status as the api returned
Delete delete_operation api method that doesn't exist
Add mocks for operations and use them in disk and server
Modified AWS S3 mock, so that it errors when creating an existing bucket

AWS S3 returns a BucketAlreadyOwnedByYou error when attempting to create a bucket that already exists, in a region other than the default. This commit modifies the mocked object to reflect this.
Merge pull request #2461 from GiMiScale/fix-mock-s3-create-bucket

Modified AWS S3 mock, so that it errors when creating an existing bucket
Merge pull request #2456 from maestrodev/google-missing-options

[google] Instances are created without description, and disk size is ignored
Merge pull request #2460 from maestrodev/google-operations

[google] Implement operation model
ecloud api version bump

fixes #2451
Merge pull request #2463 from ehowe/ecloud_version_bump

ecloud api version bump
Merge branch 'master' into maestrodev