RFR: 302: PR body updater should use .jcheck/conf from target branch

[Erik Helin]

Hi all,

please reviews this patch that makes the pull request body updater use the
.jcheck/conf from the pull request's target branch when populating the
"Progress" list.

Testing:
- Updated one unit test
- `make test` passes on Linux x64

Thanks,
Erik

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Commit messages:
 - skara-302

Changes: https://git.openjdk.java.net/skara/pull/507/files
 Webrev: https://webrevs.openjdk.java.net/skara/507/webrev.00
  Issue: https://bugs.openjdk.java.net/browse/SKARA-302
  Stats: 29 lines in 4 files changed: 1 ins; 13 del; 15 mod
  Patch: https://git.openjdk.java.net/skara/pull/507.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/507/head:pull/507

PR: https://git.openjdk.java.net/skara/pull/507