testing: adding a Hadoop wordcount test

Signed-off-by: Joe Buck <jbbuck@gmail.com>
Reviewed-by: Sam Lang <sam.lang@inktank.com>
test: correcting hadoop-internal tests

Changing the hadoop-internal tests to use the
newly added $TESTDIR environment variable.
Also, removed unneeded variables.

Signed-off-by: Joe Buck <jbbuck@gmail.com>
Reviewed-by: Sam Lang <sam.lang@inktank.com>