OAK-2342: Clean up collision markers

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1644479 13f79535-47bb-0310-9956-ffa450edef68
OAK-2343: Wrong handling of InterruptedException in BackgroundThread
Set the current's thread interrupted status

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1644490 13f79535-47bb-0310-9956-ffa450edef68
OAK-2337 - improve connection handling

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1644509 13f79535-47bb-0310-9956-ffa450edef68