I didn't find many deprecated configs after a grep-based search,
but the ones I could find were moved to the centralized location
in SparkConf.

While there, I deprecated a couple more HS configs that mentioned
time units.

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #5562 from vanzin/SPARK-5933 and squashes the following commits:

dcb617e7 [Marcelo Vanzin] [SPARK-5933] [core] Move config deprecation warnings to SparkConf.