Add crowbar-status and crowbar-failed in schema

Otherwise, barclamp_mgmt_lib.rb will edit the schema and add them, which
will make the files differ from the ones in the package.
Set proposal_schema_version to 2 in crowbar.yml

This is needed when we have crowbar-status/crowbar-failed in the schema.
Merge pull request #5 from vuntz/add-missing-attributes

Add crowbar-status and crowbar-failed in schema [18/18]