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"
```
if attribute_name in ['Arn', 'QueueArn']:
            return aws_stack.sqs_queue_arn(queue_name=self.name)
        return SQS_Queue_get_cfn_attribute_orig(self, attribute_name)
    SQS_Queue_get_cfn_attribute_orig = sqs_models.Queue.get_cfn_attribute
    sqs_models.Queue.get_cfn_attribute = SQS_Queue_get_cfn_attribute
    
    @property
    def SQS_Queue_physical_resource_id(self):
        result = SQS_Queue_physical_resource_id_orig.fget(self)
        if '://' not in result:
            
            return aws_stack.get_sqs_queue_url(result)
        return result
    SQS_Queue_physical_resource_id_orig = sqs_models.Queue.physical_resource_id
    sqs_models.Queue.physical_resource_id = SQS_Queue_physical_resource_id
    
    def Lambda_Function_get_cfn_attribute(self, attribute_name):
        try:
            if attribute_name == 'Arn':
                return self.function_arn
            return Lambda_Function_get_cfn_attribute_orig(self, attribute_name)
        except Exception:
            if attribute_name in ('Name', 'FunctionName'):
                return self.function_name
            raise
    Lambda_Function_get_cfn_attribute_orig = lambda_models.LambdaFunction.get_cfn_attribute
    lambda_models.LambdaFunction.get_cfn_attribute = Lambda_Function_get_cfn_attribute
    
    def DynamoDB_Table_get_cfn_attribute(self, attribute_name):