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 not resource:
            try:
                resource = parse_and_create_resource_orig(logical_id,
                    resource_json_arns_fixed, resources_map, region_name)
            except Exception as e:
                if should_be_created:
                    raise
                else:
                    LOG.info('Error on moto CF resource creation. Ignoring, as should_be_created=%s: %s' %
                             (should_be_created, e))
        
        if hasattr(resource, 'region_name') and resource.region_name != region_name:
            LOG.debug('Updating incorrect region from %s to %s' % (resource.region_name, region_name))
            resource.region_name = region_name
        
        if not should_be_created:
            
            if not template_deployer.is_updateable(logical_id, resource_wrapped, stack_name):
                LOG.debug('Resource %s need not be deployed: %s %s' % (logical_id, resource_json, bool(resource)))
                
                return resource
        
        update_resource_name(resource, resource_json)
        LOG.debug('Deploying CloudFormation resource (update=%s): %s' % (update, resource_json))
        try:
            CURRENTLY_UPDATING_RESOURCES[resource_hash_key] = True
            deploy_func = template_deployer.update_resource if update else template_deployer.deploy_resource
            result = deploy_func(logical_id, resource_wrapped, stack_name=stack_name)
        finally:
            CURRENTLY_UPDATING_RESOURCES[resource_hash_key] = False