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"
```
stack_name = resources_map.get('AWS::StackName')
        resource_hash_key = (stack_name, logical_id)
        
        updating = CURRENTLY_UPDATING_RESOURCES.get(resource_hash_key)
        LOG.debug('Currently updating stack resource %s/%s: %s' % (stack_name, logical_id, updating))
        if updating:
            return None
        
        resource_tuple = parsing.parse_resource(logical_id, resource_json, resources_map)
        if not resource_tuple:
            return None
        _, resource_json, _ = resource_tuple
        
        props = resource_json['Properties'] = resource_json.get('Properties') or {}
        if resource_json['Type'] == 'AWS::Lambda::EventSourceMapping' and not props.get('StartingPosition'):
            props['StartingPosition'] = 'LATEST'
        
        resource = resources_map._parsed_resources.get(logical_id)
        if resource and not update:
            return resource
        
        resource_wrapped = {logical_id: resource_json}
        should_be_created = template_deployer.should_be_deployed(logical_id, resource_wrapped, stack_name)
        
        resource_json_arns_fixed = clone(json_safe(convert_objs_to_ids(resource_json)))
        set_moto_account_ids(resource_json_arns_fixed)
        
        if resource or update:
            parse_and_update_resource_orig(logical_id,
                resource_json_arns_fixed, resources_map, region_name)