OOZIE-1454 Documentation for cron syntax scheduling of coordinator job (bowenzhangusa via rkanter)

git-svn-id: https://svn.apache.org/repos/asf/oozie/trunk@1530104 13f79535-47bb-0310-9956-ffa450edef68
Merge remote branch 'origin/trunk' into trunk
Merge remote branch 'origin/trunk' into trunk-gd