[fix] remove the unused module

[zhyass]

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Summary

I get some warnings in vscode, so I try to fix it by remove the unused module.

module `session_ref` is private  private module
unused import: `fuse_query::servers::MySQLConnection`\n\nnote: `#[warn(unused_imports)]` on by default

Changelog

• Bug Fix

Related Issues

[databend-bot]

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[databend-bot]

Hello @zhyass, 🎉 Thank you for opening the pull request! 🎉
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FuseQuery: @BohuTANG @sundy-li @zhang2014
FuseStore: @drmingdrmer @dantengsky
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[codecov-commenter]

Codecov Report

Merging #1165 (30bee0c) into master (3db2d25) will increase coverage by 0%.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master   #1165    +/-   ##
=======================================
  Coverage      70%     70%            
=======================================
  Files         441     443     +2     
  Lines       25694   26041   +347     
=======================================
+ Hits        18078   18404   +326     
- Misses       7616    7637    +21     

Impacted Files	Coverage Δ
common/runtime/src/runtime_test.rs	53% <0%> (-21%)	⬇️
fusestore/store/src/meta_service/sled_tree.rs	92% <0%> (ø)
fusestore/store/src/meta_service/sled_tree_test.rs	96% <0%> (ø)
fusestore/store/src/meta_service/raft_log.rs	97% <0%> (+<1%)	⬆️

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[databend-bot]

CI Passed
Reviewer Approved
Let's Merge