RFR: 341: Show target branch in integration message

[Erik Helin]

Hi all,

please review this small patch that clarifies which branch the commit will be
integrated to when running `/integrate`.

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

Thanks,
Erik

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Commit messages:
 - skara-341

Changes: https://git.openjdk.java.net/skara/pull/563/files
 Webrev: https://webrevs.openjdk.java.net/skara/563/webrev.00
  Issue: https://bugs.openjdk.java.net/browse/SKARA-341
  Stats: 10 lines in 2 files changed: 9 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/skara/pull/563.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/563/head:pull/563

PR: https://git.openjdk.java.net/skara/pull/563