bump executor
bump executor

[delivers #89973406]

Submodule src/github.com/cloudfoundry-incubator/executor 4ddd8e5..560c56a:
  > Use one way to send results

cloudfoundry-incubator/diego-release,cloudfoundry-incubator/diego-release,cloudfoundry-incubator/diego-release,cloudfoundry-incubator/diego-release