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"
```
try:
            if attribute_name == 'StreamArn':
                streams = aws_stack.connect_to_service('dynamodbstreams').list_streams(TableName=self.name)['Streams']
                return streams[0]['StreamArn'] if streams else None
            return DynamoDB_Table_get_cfn_attribute_orig(self, attribute_name)
        except Exception as e:
            LOG.warning('Unable to get attribute "%s" from resource %s: %s' % (attribute_name, type(self), e))
            raise
    DynamoDB_Table_get_cfn_attribute_orig = dynamodb_models.Table.get_cfn_attribute
    dynamodb_models.Table.get_cfn_attribute = DynamoDB_Table_get_cfn_attribute
    
    def IAM_Role_get_cfn_attribute(self, attribute_name):
        try:
            return IAM_Role_get_cfn_attribute_orig(self, attribute_name)
        except Exception:
            if attribute_name == 'Arn':
                return aws_stack.role_arn(self.name)
            raise
    IAM_Role_get_cfn_attribute_orig = iam_models.Role.get_cfn_attribute
    iam_models.Role.get_cfn_attribute = IAM_Role_get_cfn_attribute
    
    def SNS_Topic_get_cfn_attribute(self, attribute_name):