Deploys timeout with large dependencies

I'm building a service that depends on `googleapis` which is pretty large. My deployments are taking > 7 minutes and are failing with:

```bash
Error: deploying: eu-west-1: creating function: InvalidSignatureException: Signature expired: 20170824T084036Z is now earlier than 20170824T084309Z (20170824T084809Z - 5 min.)
status code: 403, request id: e57e39d5-88a7-11e7-b427-77ecd219e533
```

Think this issue is related: https://github.com/serverless/serverless/issues/490