To avoid a zombie apocalypse, use cmd.Wait() to properly finish the processes we spawn by Start(). Found while investigating DockerSuite.TestLogsFollowSlowStdoutConsumer failure on ARM (see https://github.com/moby/moby/pull/34550#issuecomment-324937936). [v2: don't expect no error from Wait() when process is killed] Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com> Upstream-commit: 14f0a1888f92667f82bea548bfa2fe4a890a75e8 Component: engine