OOZIE-2091:add shell scripts trigger coordinators and compatible with th...

...e dataset trigger modeHello everyone, 
I am a software engineer, worked IFLYTEK, IFLYTEK is Asia Pacific's leading intelligent voice listed companies. I work in the cloud computing sector, I found the coordinator oozie trigger mechanism datasets trigger conditions can not meet all of our company, so I added a trigger condition, shell scripts triggered. I modified the coordinator xml syntax compatible with two trigger modes, an increase of , when the coordinator will call the specified shell script, when the script returns true, coordinator will run the task of the current time. You give me somesuggestions it, this trigger mode you agree with it? Thank you!
Thank you Robert Kanter reply me and give me suggestions，it's really adding the ability to trigger coordinators based on the output ("true" or "false") of a shell script，I do not want to instead of waiting for data to be available in HDFS，I want to Compatible with both trigger mode for coordinator in order to meet all of the trigger conditions of business。I will quickly use the correct code format and make a new version of the coordinator schema。
thanks
孙盟