New kinesis syntax not working
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# This is a (Bug Report / Feature Proposal)
## Description

For bug reports:
- What went wrong?
  When I tried to convert my kinesis event mappings to the new syntax, like this:

`````` yaml

  extract:
    handler: extract/index.handler
    events:
      - stream:
          arn:
            Fn::GetAtt:
              - BookmarksStream
              - Arn

I got the following error "EventSourceArn.split is not a function"

Looking at the source code, I get the impression that this feature simply has not been implemented yet. However, it is already referenced in the docs here:

https://serverless.com/framework/docs/providers/aws/events/streams/

* What did you expect should have happened?

The cloudformation GetAtt should have resolved into a valid arn

* What was the config you used?

```yaml

  extract:
    handler: extract/index.handler
    events:
      - stream:
          arn:
            Fn::GetAtt:
              - BookmarksStream
              - Arn

* What stacktrace or error message from your provider did you see?

For feature proposals:
* What is the use case that should be solved. The more detail you describe this in the easier it is to understand for us.
* If there is additional config how would it look

Similar or dependent issues:
* #12345

## Additional Data

* ***Serverless Framework Version you're using***:
1.0.2 

* ***Operating System***:

linux (kubuntu)
* ***Stack Trace***:

TypeError: EventSourceArn.split is not a function
    at functionObj.events.forEach.event (/home/yeehaa/.nvm/versions/node/v6.8.0/lib/node_modules/serverless/lib/plugins/aws/deploy/compile/events/stream/index.js:82:47)
    at Array.forEach (native)
    at serverless.service.getAllFunctions.forEach (/home/yeehaa/.nvm/versions/node/v6.8.0/lib/node_modules/serverless/lib/plugins/aws/deploy/compile/events/stream/index.js:20:28)
    at Array.forEach (native)
    at AwsCompileStreamEvents.compileStreamEvents (/home/yeehaa/.nvm/versions/node/v6.8.0/lib/node_modules/serverless/lib/plugins/aws/deploy/compile/events/stream/index.js:16:47)
    at BbPromise.reduce (/home/yeehaa/.nvm/versions/node/v6.8.0/lib/node_modules/serverless/lib/classes/PluginManager.js:151:50)
    at tryCatcher (/home/yeehaa/.nvm/versions/node/v6.8.0/lib/node_modules/serverless/node_modules/bluebird/js/release/util.js:16:23)
    at Object.gotValue (/home/yeehaa/.nvm/versions/node/v6.8.0/lib/node_modules/serverless/node_modules/bluebird/js/release/reduce.js:157:18)
    at Object.gotAccum (/home/yeehaa/.nvm/versions/node/v6.8.0/lib/node_modules/serverless/node_modules/bluebird/js/release/reduce.js:144:25)
    at Object.tryCatcher (/home/yeehaa/.nvm/versions/node/v6.8.0/lib/node_modules/serverless/node_modules/bluebird/js/release/util.js:16:23)
    at Promise._settlePromiseFromHandler (/home/yeehaa/.nvm/versions/node/v6.8.0/lib/node_modules/serverless/node_modules/bluebird/js/release/promise.js:510:31)
    at Promise._settlePromise (/home/yeehaa/.nvm/versions/node/v6.8.0/lib/node_modules/serverless/node_modules/bluebird/js/release/promise.js:567:18)
    at Promise._settlePromise0 (/home/yeehaa/.nvm/versions/node/v6.8.0/lib/node_modules/serverless/node_modules/bluebird/js/release/promise.js:612:10)
    at Promise._settlePromises (/home/yeehaa/.nvm/versions/node/v6.8.0/lib/node_modules/serverless/node_modules/bluebird/js/release/promise.js:691:18)
    at Async._drainQueue (/home/yeehaa/.nvm/versions/node/v6.8.0/lib/node_modules/serverless/node_modules/bluebird/js/release/async.js:138:16)
    at Async._drainQueues (/home/yeehaa/.nvm/versions/node/v6.8.0/lib/node_modules/serverless/node_modules/bluebird/js/release/async.js:148:10)

* ***Provider Error messages***:

EventSourceArn.split is not a function
``````