RFR: Avoid posting Jira link comments multiple times

[Robin Westberg]

Hi all,

Please review this change that avoids potentially posting the same Jira link comment multiple times.

Best regards,
Robin

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Commit messages:
 - Avoid doubleposting

Changes: https://git.openjdk.java.net/skara/pull/784/files
 Webrev: https://webrevs.openjdk.java.net/?repo=skara&pr=784&range=00
  Stats: 9 lines in 1 file changed: 9 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/skara/pull/784.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/784/head:pull/784

PR: https://git.openjdk.java.net/skara/pull/784