[SPARK-4472][Shell] Print "Spark context available as sc." only when SparkContext is created...

... successfully

It's weird that printing "Spark context available as sc" when creating SparkContext unsuccessfully.


I think I misunderstood your question. The difference is if `org.apache.spark.repl.Main.createSparkContext()` throws an exception, the `println` won't be executed. The previous implementation will always execute `echo`.