RFR: git-jcheck: set exit code correctly

[Erik Helin]

Hi all,

please review this small patch that ensures that `JCheckCLIVisitor` correctly
sets `hasDisplayedError` for all errors. This will in turn make sure that
`git-jcheck` exits with code `1` whenever an error has been shown which in
turn will make `git create --jcheck` work correctly.

Testing:
- Manual testing of `git jcheck` and `git pr create --jcheck` on Linux x64

Thanks,
Erik

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

Commits:
 - 5bfae13b: git-jcheck: set exit code correctly

Changes: https://git.openjdk.java.net/skara/pull/464/files
 Webrev: https://webrevs.openjdk.java.net/skara/464/webrev.00
  Stats: 21 lines in 1 file changed: 19 ins; 2 del; 0 mod
  Patch: https://git.openjdk.java.net/skara/pull/464.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/464/head:pull/464

PR: https://git.openjdk.java.net/skara/pull/464