[SPARK-12241][YARN] Improve failure reporting in Yarn client obtainTokenForHBase()

This lines up the HBase token logic with that done for Hive in SPARK-11265: reflection with only CFNE being swallowed.

There is a test, one which doesn't try to put HBase on the yarn/test class and really do the reflection (the way the hive introspection does). If people do want that then it could be added with careful POM work

+also: cut an incorrect comment from the Hive test case before copying it, and a couple of imports that may have been related to the hive test in the past.

Author: Steve Loughran <stevel@hortonworks.com>

Closes #10227 from steveloughran/stevel/patches/SPARK-12241-obtainTokenForHBase.