testing: updating hadoop-internal test

Small tweaks to the hadoop-internal test
to better use existing environment varaibles
and in response to the recent teuthology
changes.

Signed-off-by: Joe Buck <jbbuck@gmail.com>
Reviewed-by: Noah Watkins <noahwatkins@gmail.com>
test: removing dead code

Signed-off-by: Joe Buck <jbbuck@gmail.com>