[KYUUBI #336] Fix a race in Kyuubi start and stop
 [](https://github.com/yaooqinn/kyuubi/pull/336)     [❨?❩](https://pullrequestbadge.com/?utm_medium=github&utm_source=yaooqinn&utm_campaign=badge_info)<!-- PR-BADGE: PLEASE DO NOT REMOVE THIS COMMENT -->
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### _Why are the changes needed?_
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there is something wrong with Travis these days due to some newly added test cases
### _How was this patch tested?_
- [ ] Add some test cases that check the changes thoroughly including negative and positive cases if possible
- [ ] Add screenshots for manual tests if appropriate
- [x] [Run test](https://kyuubi.readthedocs.io/en/latest/tools/testing.html#running-tests) locally before make a pull request
Closes #336 from yaooqinn/travisagain.
0285f5a [Kent Yao] fix a race
3624889 [Kent Yao] fix a race
895b4d5 [Kent Yao] fix a race
e253b9c [Kent Yao] fix a race
75d699a [Kent Yao] fix a race
7bde6b9 [Kent Yao] nit
6959e42 [Kent Yao] nit
062a151 [Kent Yao] nit
ca8af10 [Kent Yao] kyuubi-common
6e4b8b6 [jhx1008] Try to restore travis
Lead-authored-by: Kent Yao <yao@apache.org>
Co-authored-by: jhx1008 <jhx1008@gmail.com>
Signed-off-by: Kent Yao <yao@apache.org>
7deb2f7fd7