RFR: 2653: Inconsistent parsing of PR titles

[Zhao Song]

Right now, if the user put space between issue id and colon, the regex can't parse it correctly, this patch is trying to fix it.

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Commit messages:
 - 2653

Changes: https://git.openjdk.org/skara/pull/1749/files
  Webrev: https://webrevs.openjdk.org/?repo=skara&pr=1749&range=00
  Issue: https://bugs.openjdk.org/browse/SKARA-2653
  Stats: 3 lines in 3 files changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/skara/pull/1749.diff
  Fetch: git fetch https://git.openjdk.org/skara.git pull/1749/head:pull/1749

PR: https://git.openjdk.org/skara/pull/1749