This is used to keep track of the deployment status. The status file
is kept under the 'state' dir. The check() method is used to find
conflicting components or the ones that have already been installed.
The update() method adds an entry in the node's section. If in dry-run
this file is not written back to permanent storage (kept in memory).

Signed-off-by: Dimitris Aragiorgis <dimara@grnet.gr>