[SPARK-1233] Fix running hadoop 0.23 due to java.lang.NoSuchFieldException: DEFAULT_M...

...APREDUCE_APPLICATION_CLASSPATH

Author: Thomas Graves <tgraves@apache.org>

Closes #129 from tgravescs/SPARK-1233 and squashes the following commits:

85ff5a6 [Thomas Graves] Fix running hadoop 0.23 due to java.lang.NoSuchFieldException: DEFAULT_MAPREDUCE_APPLICATION_CLASSPATH
Simple sc sharing between repls