when timeout reached, change "Paragraph received a SIGTERM. ExitValue: 143" to a more user-friendly message

ERROR [2017-04-23 21:31:17,578] ({pool-2-thread-3} ShellInterpreter.java[interpret]:97) - Can not run hadoop fs -put /vol/srcfile /user/rdautkha/dstfile
org.apache.commons.exec.ExecuteException: Process exited with an error: 143 (Exit value: 143)
        at org.apache.commons.exec.DefaultExecutor.executeInternal(DefaultExecutor.java:404)
        at org.apache.commons.exec.DefaultExecutor.execute(DefaultExecutor.java:166)
        at org.apache.commons.exec.DefaultExecutor.execute(DefaultExecutor.java:153)
        at org.apache.zeppelin.shell.ShellInterpreter.interpret(ShellInterpreter.java:91)
        at org.apache.zeppelin.interpreter.LazyOpenInterpreter.interpret(LazyOpenInterpreter.java:94)
        at org.apache.zeppelin.interpreter.remote.RemoteInterpreterServer$InterpretJob.jobRun(RemoteInterpreterServer.java:495)
        at org.apache.zeppelin.scheduler.Job.run(Job.java:181)
        at org.apache.zeppelin.scheduler.ParallelScheduler$JobRunner.run(ParallelScheduler.java:162)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
        at java.util.concurrent.FutureTask.run(FutureTask.java:262)
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:178)
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:292)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:745)