[bug] some test case run failed

[hustjieke]

sometimes next test cases run failed.

=== RUN   TestNormalTicker
        Error Trace:    common_test.go:85
        Error:		Not equal: 
        	expected: 1
        	received: 0
        
--- FAIL: TestNormalTicker (0.10s)


=== RUN   TestCommand
        Error Trace:    linux_test.go:71
        Error:		Expected nil, but got: cmd.outs.[sleep: missing operand].found[0]!=expects[1]
        
--- FAIL: TestCommand (0.03s)

[CrookedPotato]

run make test failed xenon ：Xenon v1.1.4 CentOS Linux release 7.8.2003 (Core)

=== RUN TestRunCommand --- PASS: TestRunCommand (0.00s) === RUN TestCommand Error Trace: linux_test.go:68 Error: Expected nil, but got: cmd.outs.[sleep: missing operand].found[0]!=expects[1]

--- FAIL: TestCommand (0.01s) FAIL FAIL xbase/common 1.640s FAIL make[1]: *** [testcommon] 错误 1 make[1]: 离开目录“/data/xenon”

[CrookedPotato]

this case will cause ./xenoncli mysql rebuildme or sshpass ssh exec command failed