fix bug: Null pointer from hh caused panic #3

[andyli029]

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• InfluxQL Spec updated
• Provide example syntax
• Update man page when modifying a command
• Config changes: update sample config (etc/config.sample.toml), server NewDemoConfig method, and Diagnostics methods reporting config settings, if necessary
• InfluxData Documentation: issue filed or pull request submitted <link to issue or pull request>

[andyli029]

Issue: andyli029#3

@chengshiwen
Please take a look

[chengshiwen]

@andyli029 LGTM🎉

Thanks for your contribution, and I will merge this PR after the CI check is done