[SPARK-13086][Shell] Use the Scala REPL settings, to enable things like -i file.

[dragos]

Now:

$ bin/spark-shell -i test.scala 
NOTE: SPARK_PREPEND_CLASSES is set, placing locally compiled Spark classes ahead of assembly.
Setting default log level to "WARN".
To adjust logging level use sc.setLogLevel(newLevel).
16/01/29 17:37:38 WARN NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
16/01/29 17:37:39 INFO Main: Created spark context..
Spark context available as sc (master = local[*], app id = local-1454085459000).
16/01/29 17:37:39 INFO Main: Created sql context..
SQL context available as sqlContext.
Loading test.scala...
hello

Welcome to
      ____              __
     / __/__  ___ _____/ /__
    _\ \/ _ \/ _ `/ __/  '_/
   /___/ .__/\_,_/_/ /_/\_\   version 2.0.0-SNAPSHOT
      /_/

Using Scala version 2.11.7 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_45)
Type in expressions to have them evaluated.
Type :help for more information.

[SparkQA]

Test build #50385 has finished for PR 10984 at commit ba19bfd.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[dragos]

@jodersky @CodingCat can you have a look? I think you've look at this part of the code in the past.

[jodersky]

Looks good to me.

[CodingCat]

LGTM

[srowen]

Merged to master