bump executor
bump executor

[finishes #154321605]

Submodule src/code.cloudfoundry.org/executor c50f4227..f8c47dd1:
  > uncomment an accidentally commented out line

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