When trying to deploy a serverless service that does not currently deploy correctly onto localstack using a custom deployment bucket, the lambdas seems to be created regardless (???) but not as part of the stack, with localstack outputting `botocore.errorfactory.ResourceConflictException: An error occurred (ResourceConflictException) when calling the CreateFunction operation: Function already exist` .

For example, the `serverless.yml` below would currently fail to deploy due to  #1676 , but because a `deploymentBucket` was added, it will instead fail due to `Function already exist`. Subsequently removing `deploymentBucket` or even `events` from the the file will not allow it to deploy - it will fail until localstack is restarted ( or until the lambda is manually deleted?).

I've also reproduced this with services suffering from #1675. 

```yaml
service: "localtest"

provider:
  name: "aws"
  runtime: "nodejs10.x"
  deploymentBucket:
    name: "testbucket"

functions:
  hello:
    handler: "handler.hello"
    events:
      - schedule: "cron(0 * * * ? *)"

plugins:
- "serverless-localstack"

custom:
  localstack:
    stages:
      - "local"
```
elif isinstance(resource, apigw_models.Resource):
            api_id = props['RestApiId']
            backend.apis[api_id].resources.pop(resource.id, None)
            backend.apis[api_id].resources[new_id] = resource
            resource.id = new_id
        elif isinstance(resource, apigw_models.Deployment):
            api_id = props['RestApiId']
            backend.apis[api_id].deployments.pop(resource['id'], None)
            backend.apis[api_id].deployments[new_id] = resource
            resource['id'] = new_id
        else:
            LOG.warning('Unexpected resource type when updating ID: %s' % type(resource))
    parse_and_create_resource_orig = parsing.parse_and_create_resource
    parsing.parse_and_create_resource = parse_and_create_resource
    parse_and_update_resource_orig = parsing.parse_and_update_resource
    parsing.parse_and_update_resource = parse_and_update_resource
    
    def parse_output(output_logical_id, output_json, resources_map):
        try:
            return parse_output_orig(output_logical_id, output_json, resources_map)
        except KeyError:
            output = Output()
            output.key = output_logical_id
            output.value = None
            output.description = output_json.get('Description')
            return output
    parse_output_orig = parsing.parse_output
    parsing.parse_output = parse_output
    
    def DynamoDB_Table_get_cfn_attribute(self, attribute_name):