remove useless code

[zhaoyuguang]

Ⅰ. Describe what this PR did

In LockStoreDataBaseDAO::doAcquireLock, The internal property ResultSet and related code are not necessary.

[codecov-io]

Codecov Report

Merging #1205 into develop will increase coverage by 0.01%.
The diff coverage is n/a.

@@              Coverage Diff              @@
##             develop    #1205      +/-   ##
=============================================
+ Coverage      43.53%   43.54%   +0.01%     
  Complexity      1428     1428              
=============================================
  Files            250      250              
  Lines          10213    10208       -5     
  Branches        1331     1330       -1     
=============================================
- Hits            4446     4445       -1     
+ Misses          5182     5179       -3     
+ Partials         585      584       -1

Impacted Files	Coverage Δ	Complexity Δ
...a/io/seata/core/store/db/LockStoreDataBaseDAO.java	49.01% <ø> (+0.91%)	18 <0> (ø)	⬇️

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[xingfudeshi]

LGTM.

[slievrly]

LGTM