[SPARK-6731] [CORE] Addendum: Upgrade Apache commons-math3 to 3.4.1

(This finishes the job by removing the version overridden by Hadoop profiles.)

See discussion at https://github.com/apache/spark/pull/6994#issuecomment-119113167

Author: Sean Owen <sowen@cloudera.com>

Closes #7261 from srowen/SPARK-6731.2 and squashes the following commits:

5a3f59e [Sean Owen] Finish updating Commons Math3 to 3.4.1 from 3.1.1