Add get_schema() method to Json field type
Add get_schema() method to Json field type

This patch adds a get_schema() call to Json field type. It is required
in future to generate Json schema out of a field type so that input Json
can be validated.

Change-Id: I8b9f3e037c6b1cd8ca4167b07b62272bfce82bab

stackforge/senlin,openstack/senlin,openstack/senlin,openstack/senlin,stackforge/senlin