STORM-532,Supervisor should restart worker immediately, if the worker pr...

https://issues.apache.org/jira/browse/STORM-532

For now 
if the worker process does not exist any more 
Supervisor will have to wait a few seconds for worker heartbeart timeout and restart worker .

If supervisor knows the worker processid and check if the process exists in the sync-processes thread ,may need less time to restart worker.
1: record worker process id in the worker local heartbeart 
2: in supervisor sync-processes ,get process id from worker local heartbeat 
and check if the process exits 
3: if not restart it immediately
exists-linux-process