Fix TestDockerCmd*Timeout racey tests

Signed-off-by: Vincent Demeester <vincent@sbr.pm>

integration/utils.go

@@ -105,8 +105,16 @@ func RunCommandWithOutputForDuration(cmd *exec.Cmd, duration time.Duration) (out
 	cmd.Stderr = &outputBuffer
 
 	done := make(chan error)
+
+	// Start the command in the main thread..
+	err = cmd.Start()
+	if err != nil {
+		err = fmt.Errorf("Fail to start command %v : %v", cmd, err)
+	}
+
 	go func() {
-		exitErr := cmd.Run()
+		// And wait for it to exit in the goroutine :)
+		exitErr := cmd.Wait()
 		exitCode = ProcessExitCode(exitErr)
 		done <- exitErr
 	}()