[feature] optimize code on install tokudb in init.go

[hustjieke]

Is your feature request related to a problem? Please describe.

                cmd.Stderr = os.Stderr
                if err = cmd.Run(); err != nil {
                        return fmt.Errorf("failed to disable the transparent_hugepage: %s", err)
                }   

Describe the solution you'd like

use cmd.CombinedOutput() instead of cmd.Stderr = os.Stderr cmd.Run()

Describe alternatives you've considered

Additional context