RFR: 2089: Warn when bug fixVersion doesn't match .jcheck/conf version in PR [v2]

[Zhao Song]

> This patch tries to alert the user when the fixVersion in the issue differs from the fixVersion in .jcheck/conf, thereby preventing the creation of unwanted backports.

Zhao Song has updated the pull request incrementally with one additional commit since the last revision:

  add fixVersionOverride option

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Changes:
  - all: https://git.openjdk.org/skara/pull/1585/files
  - new: https://git.openjdk.org/skara/pull/1585/files/f4285ec3..9a61116e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=skara&pr=1585&range=01
 - incr: https://webrevs.openjdk.org/?repo=skara&pr=1585&range=00-01

  Stats: 66 lines in 5 files changed: 60 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/skara/pull/1585.diff
  Fetch: git fetch https://git.openjdk.org/skara.git pull/1585/head:pull/1585

PR: https://git.openjdk.org/skara/pull/1585