Fix results object when throwing exception while running job

 INFO [2018-04-27 12:51:28,562] ({pool-2-thread-3} SchedulerFactory.java[jobStarted]:109) - Job 20180427-123612_1851631951 started by scheduler interpreter_1108320718
 INFO [2018-04-27 12:51:28,564] ({pool-2-thread-3} OldSparkInterpreter.java[populateSparkWebUrl]:930) - Sending metadata to Zeppelin server: {message=Spark UI enabled, url=http://10.133.69.85:4041}
 INFO [2018-04-27 12:51:28,567] ({pool-2-thread-3} Logging.scala[logInfo]:54) - Parsing command: show tables invalid
ERROR [2018-04-27 12:51:28,569] ({pool-2-thread-3} Job.java[run]:185) - Job failed
org.apache.zeppelin.interpreter.InterpreterException: java.lang.reflect.InvocationTargetException
        at org.apache.zeppelin.spark.SparkSqlInterpreter.interpret(SparkSqlInterpreter.java:123)
        at org.apache.zeppelin.interpreter.LazyOpenInterpreter.interpret(LazyOpenInterpreter.java:103)
        at org.apache.zeppelin.interpreter.remote.RemoteInterpreterServer$InterpretJob.jobRun(RemoteInterpreterServer.java:623)
        at org.apache.zeppelin.scheduler.Job.run(Job.java:183)
        at org.apache.zeppelin.scheduler.FIFOScheduler$1.run(FIFOScheduler.java:140)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180)
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.reflect.InvocationTargetException
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at org.apache.zeppelin.spark.SparkSqlInterpreter.interpret(SparkSqlInterpreter.java:120)
        ... 11 more
Caused by: org.apache.spark.sql.catalyst.parser.ParseException:
extraneous input 'invalid' expecting <EOF>(line 1, pos 12)

== SQL ==
show tables invalid
------------^^^

        at org.apache.spark.sql.catalyst.parser.ParseException.withCommand(ParseDriver.scala:197)
        at org.apache.spark.sql.catalyst.parser.AbstractSqlParser.parse(ParseDriver.scala:99)
        at org.apache.spark.sql.execution.SparkSqlParser.parse(SparkSqlParser.scala:45)
        at org.apache.spark.sql.catalyst.parser.AbstractSqlParser.parsePlan(ParseDriver.scala:53)
        at org.apache.spark.sql.SparkSession.sql(SparkSession.scala:600)
        at org.apache.spark.sql.SQLContext.sql(SQLContext.scala:699)
        ... 16 more
 INFO [2018-04-27 12:51:28,570] ({pool-2-thread-3} SchedulerFactory.java[jobFinished]:115) - Job 20180427-123612_1851631951 finished by scheduler interpreter_1108320718
ERROR [2018-04-27 12:51:28,570] ({pool-1-thread-5} TThreadPoolServer.java[run]:296) - Error occurred during processing of message.
java.lang.ClassCastException: java.lang.String cannot be cast to org.apache.zeppelin.interpreter.InterpreterResult
        at org.apache.zeppelin.interpreter.remote.RemoteInterpreterServer.interpret(RemoteInterpreterServer.java:456)
        at org.apache.zeppelin.interpreter.thrift.RemoteInterpreterService$Processor$interpret.getResult(RemoteInterpreterService.java:1859)
        at org.apache.zeppelin.interpreter.thrift.RemoteInterpreterService$Processor$interpret.getResult(RemoteInterpreterService.java:1844)
        at org.apache.thrift.ProcessFunction.process(ProcessFunction.java:39)
        at org.apache.thrift.TBaseProcessor.process(TBaseProcessor.java:39)
        at org.apache.thrift.server.TThreadPoolServer$WorkerProcess.run(TThreadPoolServer.java:285)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at java.lang.Thread.run(Thread.java:745)