test: Hadoop cluster and task config.

Add a 3-node cluster specification and a
task for running wordcount with Hadoop on Ceph.

Signed-off-by: Joe Buck <jbbuck@gmail.com>
test: task for hadoop internal tests.

Run the TestCephFileSystem tests against our
branch of hadoop-common.

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