playground: fix wrong flag name

[srstack]

What problem does this PR solve?

playground db.host,db.port,pd.host changed to db.Host, db.Port and pd.Host, need to be restored
Close #1632

What is changed and how it works?

to

Check List

Tests

• No code

Code changes

• Has persistent data change

Release notes:

NONE

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• AstroProfundis

To complete the pull request process, please ask the reviewers in the list to review by filling /cc @reviewer in the comment.
After your PR has acquired the required number of LGTMs, you can assign this pull request to the committer in the list by filling /assign @committer in the comment to help you merge this pull request.

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

Reviewer can indicate their review by submitting an approval review.
Reviewer can cancel approval by submitting a request changes review.

[CLAassistant]

All committers have signed the CLA.

[codecov-commenter]

Codecov Report

Merging #1635 (8c16c2b) into master (a713f26) will not change coverage.
The diff coverage is n/a.

❗ Current head 8c16c2b differs from pull request most recent head e461aa8. Consider uploading reports for the commit e461aa8 to get more accurate results

@@           Coverage Diff           @@
##           master    #1635   +/-   ##
=======================================
  Coverage   15.59%   15.59%           
=======================================
  Files         151      151           
  Lines       15234    15234           
=======================================
  Hits         2376     2376           
  Misses      12341    12341           
  Partials      517      517           

Flag	Coverage Δ
integrate	15.59% <ø> (ø)
tiup	15.59% <ø> (ø)
unittest	?

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

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update a713f26...e461aa8. Read the comment docs.

[ti-chi-bot]

@zhangyangyu: Thanks for your review. The bot only counts approvals from reviewers and higher roles in list, but you're still welcome to leave your comments.

In response to this:

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.

[srstack]

/merge

[ti-chi-bot]

@srstack: /merge is only allowed for the committers, you can assign this pull request to the committer in list by filling /assign @committer in the comment to help merge this pull request.

In response to this:

/merge

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.

[nexustar]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: e461aa8