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### _Why are the changes needed?_
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To make the error message more clear when `SPARK_HOME` is invalid.
### _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
- [ ] [Run test](https://kyuubi.readthedocs.io/en/latest/develop_tools/testing.html#running-tests) locally before make a pull request
Closes#1013 from pan3793/sh.
Closes#1013
c9a573b1 [Cheng Pan] nit
e1628640 [Cheng Pan] indent with 2 spaces
68a767f5 [Cheng Pan] Address comments
59d4f076 [Cheng Pan] Enhance load-kyuubi-env.sh
Authored-by: Cheng Pan <chengpan@apache.org>
Signed-off-by: Kent Yao <yao@apache.org>
5edc5066f2