[SPARK-15526][ML][FOLLOWUP] Make JPMML provided scope to avoid including...

[SPARK-15526][ML][FOLLOWUP] Make JPMML provided scope to avoid including unshaded JARs, and repromote to compile in MLlib

Following the comment at https://issues.apache.org/jira/browse/SPARK-15526?focusedCommentId=16086106&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-16086106 -- this change actually needed a little more work to be complete.

This also marks JPMML as `provided` to make sure its JARs aren't included in the `jars` output, but then scopes to `compile` in `mllib`. This is how Guava is handled.

Checked result in `assembly/target/scala-2.11/jars` to verify there are no JPMML jars. Maven and SBT builds still work.

Author: Sean Owen <sowen@cloudera.com>

Closes #18637 from srowen/SPARK-15526.2.