RFR: 1935: Show issue priority as Pn rather than "n"

[Zhao Song]

Show issue priority as Pn rather than "n"

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Commit messages:
 - SKARA-1935

Changes: https://git.openjdk.org/skara/pull/1527/files
 Webrev: https://webrevs.openjdk.org/?repo=skara&pr=1527&range=00
  Issue: https://bugs.openjdk.org/browse/SKARA-1935
  Stats: 6 lines in 2 files changed: 0 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/skara/pull/1527.diff
  Fetch: git fetch https://git.openjdk.org/skara.git pull/1527/head:pull/1527

PR: https://git.openjdk.org/skara/pull/1527