Upgraded the version of the checkstyle plugin and moved its phase to `process-test-classes`. This way it will fail before the tests have been run, if necessary.
Reverted some incorrect test fixes after the change of the repository bus implementation.
MODE-2190 Fixed the way locks are cleaned up and added some more safeguard checks in the case locks are removed concurrently.
Merge pull request #1109 from hchiorean/MODE-2190

MODE 2190 - Fixed the way locks are cleaned up and added some more safe guard checks in the case locks are removed concurrently.