[flaky test] PouchRestartSuite.TestPouchRestart fails unexpectedly

[allencloud]

Ⅰ. Issue Description

When I searching Ci failure of pr #1307, I found some flaky test there. And I try to reproduce them in the CI system and on my local machine. Unfortunately, I failed to make it.

Here is the flaky test error message. While although it is flaky, I have no idea about what happened in the test case. I am wondering if we could find a way to throw out some detailed error message? @Letty5411

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FAIL: /go/src/github.com/alibaba/pouch/test/cli_restart_test.go:34: PouchRestartSuite.TestPouchRestart
/go/src/github.com/alibaba/pouch/test/cli_restart_test.go:40:
    c.Assert(res.Error, check.IsNil)
... value *exec.ExitError = &exec.ExitError{ProcessState:(*os.ProcessState)(0xc420cb56c0), Stderr:[]uint8(nil)} ("exit status 1")

Ⅱ. Describe what happened

Ⅲ. Describe what you expected to happen

Ⅳ. How to reproduce it (as minimally and precisely as possible)

Ⅴ. Anything else we need to know?

Ⅵ. Environment:

• pouch version (use pouch version):
• OS (e.g. from /etc/os-release):
• Kernel (e.g. uname -a):
• Install tools:
• Others:

[Letty5411]

The following c.Assert could be changed to res.Assert

        res := command.PouchRun("restart", "-t", "1", name)
	c.Assert(res.Error, check.IsNil)