OAK-1975: Wrong values reported for OBSERVATION_EVENT_DURATION
merged revision 1611313

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/branches/1.0@1611330 13f79535-47bb-0310-9956-ffa450edef68
Merge resivion 1611332

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/branches/1.0@1611333 13f79535-47bb-0310-9956-ffa450edef68