Add Hadoop element for creating Fedora cloud image for Savanna v0.2.

* ssh configuration
* java and hadoop installation from tmp directory
* setup network connection

Implements blueprint savanna-image-elements
Fixes bug: https://bugs.launchpad.net/savanna/+bug/1188442

Change-Id: I5b6c6ef3b78e29967b7869e3499f6c146d309dae