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.

Part of https://bugzilla.novell.com/show_bug.cgi?id=776583
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 #33 from vuntz/add-missing-attributes

Add crowbar-status and crowbar-failed in schema [8/18]
Added NTP support for windows.

Added the support for storing the NTP server information on windows platform.
Fixed the case of empty NTP list

If there is no NTP server, do not set any default.