RFR: jcheck: always reload configuration

[Erik Helin]

Hi all,

please review this pull request that always reloads the .jcheck/conf from the
tree corresponding to a commit when checking said commit. The existing
optimization may not work that well with merged histories where there are two
branches with differing .jcheck/conf files. The performance impact from this
patch is barely noticeable, so I suggest we opt for a safer and simpler
implementation.

Testing:
- `make test` passes on Linux x64

Thanks,
Erik

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Commit messages:
 - jcheck: always reload configuration

Changes: https://git.openjdk.java.net/skara/pull/492/files
 Webrev: https://webrevs.openjdk.java.net/skara/492/webrev.00
  Stats: 18 lines in 1 file changed: 0 ins; 17 del; 1 mod
  Patch: https://git.openjdk.java.net/skara/pull/492.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/492/head:pull/492

PR: https://git.openjdk.java.net/skara/pull/492