Do not try to setup missing deployment settings for Docker.

Docker has no tasks for packageBin/etc. It should not be mentioned
in the deploymentSettings definition. Otherwise, adding
deploymentSettings to your build results in:
Reference to undefined setting:

  docker:packageBin from docker:$local (build.sbt:3)
Merge pull request #251 from garycoady/fix/no-docker-publish

Do not try to setup missing deployment settings for Docker.