use_docker: false doesn't work as expected

[MaG21]

Describe the bug
use_docker: false One would expected this option to skip docker all together and do its thing. However it doesn't do that and instead doesn't include the native libs.

Use case: use_docker: false is useful for cases where serverless is already running in a codebuild container, there's no need to launch docker because codebuild can be used to compile layers.

In my case I cannot strip the serverless process out of codebuild so instead I had to configure codebuild to able able to run docker, run docker, then do the serverless deploy. painful.