Correct context of environment variables

Prior change did not have much effect, since the start/stop scripts
incorrectly set the source_env mode to "build" instead of "run".

Also remove variables for hbase_extension jar file that is no longer
used.

Change-Id: I22ab0ce6ff6c784c0f5a83d9afecda0ee60b5fbd
blueprint: bp/infra-build-hadoop-deps