CLOUDIFY-1535 Added service state to abstract node implementation.
CLOUDIFY-1535 Create ephemeral node only on client re-creation.

- Create ephemeral node only on client re-creation.
- Removed unused znode member.
- Removed already exists unit test in abstract implementation.
- Stop the node service on ephemeral node creation failure.
- Improved messages logging.
CLOUDIFY-1535 added enum javadoc.