RFR: Use a stable creation date for new revisions

[Robin Westberg]

Hi all,

Please review this change that ensures that a stable creation date is used when creating emails for new content in a PR. Otherwise they may get stuck in cooldown forever.

Best regards,
Robin

-------------

Commits:
 - ba1a0516: Use a stable creation date for new revisions

Changes: https://git.openjdk.java.net/skara/pull/422/files
 Webrev: https://webrevs.openjdk.java.net/skara/422/webrev.00
  Stats: 159 lines in 3 files changed: 151 ins; 0 del; 8 mod
  Patch: https://git.openjdk.java.net/skara/pull/422.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/422/head:pull/422

PR: https://git.openjdk.java.net/skara/pull/422