OAK-2294: Corrupt repository after concurrent version operations
IT verifying the corruption protection

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1642954 13f79535-47bb-0310-9956-ffa450edef68
OAK-2294: Corrupt repository after concurrent version operations
Log errors on cleanup but don't fail the test

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1642959 13f79535-47bb-0310-9956-ffa450edef68