AMBARI-1674. Jobtracker metric for maps_completed shows wrong value

git-svn-id: https://svn.apache.org/repos/asf/incubator/ambari/trunk@1464653 13f79535-47bb-0310-9956-ffa450edef68
AMBARI-1787. Nagios script causes Datanode error. (swagle)

git-svn-id: https://svn.apache.org/repos/asf/incubator/ambari/trunk@1464664 13f79535-47bb-0310-9956-ffa450edef68