Nondescript error returned from aws cloudformation deploy

I am running `aws cloudformation deploy` and I see in the console:

```
Waiting for changeset to be created..

'Status'
```

The return code is 255. When I look in the CloudFormation console, I see that the changeset has been created successfully, but the state is `REVIEW_IN_PROGRESS`. I expected this command to create the changeset and then execute it, but it seems there was an error in the process.

I did some digging in the AWS CLI source code and believe I found the issue, which I would like to report as a bug:

The reason the console shows `Status` is due to a KeyError occuring at:

https://github.com/aws/aws-cli/blob/648637cb5a09e71a99577a58bf967038ace2943c/awscli/customizations/cloudformation/deployer.py#L168

The cloudformation client is returning an error reporting that certain IAM permissions are missing. However, the response does not contain a `Status` property as expected by the line above. Instead, the response contains an `Error` object.