Revert "fix deleteAvailableLimit bug (#1481)"

[zmberg]

This fix is incorrect.

This reverts commit f4e238f.

Ⅰ. Describe what this PR does

Ⅱ. Does this pull request fix one issue?

Ⅲ. Describe how to verify it

Ⅳ. Special notes for reviews

[codecov]

Codecov Report

Attention: 4 lines in your changes are missing coverage. Please review.

Comparison is base (6f1b1d4) 47.94% compared to head (1597112) 48.58%.
Report is 3 commits behind head on master.

Files	Patch %	Lines
pkg/controller/cloneset/sync/cloneset_scale.go	50.00%	0 Missing and 4 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1487      +/-   ##
==========================================
+ Coverage   47.94%   48.58%   +0.64%     
==========================================
  Files         157      157              
  Lines       22432    22480      +48     
==========================================
+ Hits        10754    10921     +167     
+ Misses      10487    10356     -131     
- Partials     1191     1203      +12     

Flag	Coverage Δ
unittests	48.58% <63.63%> (+0.64%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[FillZpp]

/lgtm

[zmberg]

/approve

[kruise-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: zmberg

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [zmberg]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[huaouo]

Could you please explain why should we keep to use deleteReadyLimit rather than deleteAvailableLimit despite that deleteReadyLimit is calculated from maxUnavailable and totalUnavailable