cluster: Allows setting other storage config for TiFlash when storage.main is not defined

[breezewish]

What problem does this PR solve?

TiUP Cluster will reject the deployment for the following TiFlash config:

config:
  storage.remote.dir: /tmp/tiflash/remote

Actually this is fine: TiFlash does not require storage.main defined in this case.

What is changed and how it works?

Only check storage.main exists when storage.latest or storage.raft is defined.

Check List

Tests

• Unit test

Release notes:

Allows setting other storage config for TiFlash when `storage.main` is not defined

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• kaaaaaaang

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[codecov-commenter]

Codecov Report

Patch coverage: 100.00% and project coverage change: -13.92 ⚠️

Comparison is base (a35df90) 56.07% compared to head (d39e4eb) 42.15%.

❗ Current head d39e4eb differs from pull request most recent head 598a9c8. Consider uploading reports for the commit 598a9c8 to get more accurate results

Additional details and impacted files

@@             Coverage Diff             @@
##           master    #2161       +/-   ##
===========================================
- Coverage   56.07%   42.15%   -13.92%     
===========================================
  Files         317      317               
  Lines       33575    33567        -8     
===========================================
- Hits        18825    14147     -4678     
- Misses      12501    17735     +5234     
+ Partials     2249     1685      -564     

Flag	Coverage Δ
cluster	?
dm	26.07% <0.00%> (+0.05%)	⬆️
playground	15.35% <0.00%> (+0.01%)	⬆️
tiup	16.02% <0.00%> (+0.01%)	⬆️
unittest	22.66% <100.00%> (-0.02%)	⬇️

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

Impacted Files	Coverage Δ
pkg/cluster/spec/tiflash.go	44.46% <100.00%> (-24.57%)	⬇️

... and 125 files with indirect coverage changes

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[JaySon-Huang]

LGTM

[ti-chi-bot]

@JaySon-Huang: 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:

LGTM

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[kaaaaaaang]

/merge

[ti-chi-bot]

@kaaaaaaang: /merge in this pull request requires 1 approval(s).

In response to this:

/merge

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[kaaaaaaang]

/merge

[ti-chi-bot]

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

Commit hash: 598a9c8