[fix] runmode=debug not work

[gohalo]

What problem does this PR solve?

Issue Number: close #443

Problem Summary:
When the compute node crash, and then set run mode to debug with the following commands.

kubectl annotate pod hello-simple-doris-cg2-0 selectdb.com.doris/runmode=debug
kubectl annotate pod hello-simple-doris-cg2-0 apache.com.doris/runmode=debug

But the be process still startup which is unexpected.

Because the following /etc/podinfo is not mounted, and then the doris-debug command failed to check.

Release note

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Check List (For Author)

• Test

  • Regression test
  • Unit Test
  • Manual test (add detailed scripts or steps below)
  • No need to test or manual test. Explain why:
    • This is a refactor/code format and no logic has been changed.
    • Previous test can cover this change.
    • No code files have been changed.
    • Other reason

• Behavior changed:

  • No.
  • Yes.

• Does this need documentation?

  • No.
  • Yes.

Check List (For Reviewer who merge this PR)

• Confirm the release note
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