OOZIE-1499 Update only necessary columns and consolidate JPA Executors (ryota)

git-svn-id: https://svn.apache.org/repos/asf/oozie/trunk@1520716 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/trunk' into trunk
Merge remote branch 'origin/trunk' into trunk-gd