OOZIE-1424 Improve SLA reliability on restart, fix bugs related to SLA and event generation (virag)

git-svn-id: https://svn.apache.org/repos/asf/oozie/trunk@1495272 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/trunk' into trunk
Merge remote branch 'origin/trunk' into trunk-gd
Merge remote branch 'origin/trunk-gd' into fb-OOZIE-1417-trunk-gd