RFR: 1026: Skara bot doesn't update Progress checklist for clean backports to show that it is properly reviewed

[Erik Joelsson]

When a backport is considered clean, no review is required. This should be reflected in the progress list in the PR body. This patch simply removes the "Change must be properly reviewed" line in that case.

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Commit messages:
 - Add check in test for non clean backport
 - SKARA-1026

Changes: https://git.openjdk.java.net/skara/pull/1198/files
 Webrev: https://webrevs.openjdk.java.net/?repo=skara&pr=1198&range=00
  Issue: https://bugs.openjdk.java.net/browse/SKARA-1026
  Stats: 21 lines in 4 files changed: 13 ins; 0 del; 8 mod
  Patch: https://git.openjdk.java.net/skara/pull/1198.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/1198/head:pull/1198

PR: https://git.openjdk.java.net/skara/pull/1198