RFR: 1674: Skara bot is not closing the bug after merge request is integrated

[Magnus Ihse Bursie]

This is a tentative fix for [SKARA-1674](https://bugs.openjdk.org/browse/SKARA-1674). This fix simply reverts [SKARA-1479](https://bugs.openjdk.org/browse/SKARA-1479). It will (most likely) fix the more urgent issue of the bots not being able to close pull requests, at the expense of reintroducing the problem with the Dukebot user assignment that SKARA-1479 tried to fix.

Unfortunately Erik is out of office, so I think this is the best we can do at the moment, and then we can file a REDO bug for SKARA-1479, to re-implement it but more robustly.

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Commit messages:
 - 1674: Skara bot is not closing the bug after merge request is integrated

Changes: https://git.openjdk.org/skara/pull/1419/files
 Webrev: https://webrevs.openjdk.org/?repo=skara&pr=1419&range=00
  Issue: https://bugs.openjdk.org/browse/SKARA-1674
  Stats: 5 lines in 1 file changed: 0 ins; 4 del; 1 mod
  Patch: https://git.openjdk.org/skara/pull/1419.diff
  Fetch: git fetch https://git.openjdk.org/skara pull/1419/head:pull/1419

PR: https://git.openjdk.org/skara/pull/1419