Added swift-container-info tool.

This is a very simple swift tool to retrieve information
of a container that is located on the storage node.
One can call the tool with a given container db file
as it is stored on the storage node system.
It will then return several information about that container.

Change-Id: Ifebaed6c51a9ed5fbc0e7572bb43ef05d7dd254b
Merge "Added swift-container-info tool."