In test can't update resources on packages created before scheming migration

[jachurchill]

Currently, when a user updates a single resource, all existing resources are validated (this is a core CKAN functionality). If any resource is invalid, then it's impossible to update another.

Many resources (especially geographic datasets) are not validating because mandatory fields are not set to any value. We need to set these mandatory fields properly to allow for proper validation.

To fix this we will need to:

• set reasonable default values; and
• update the migration script to support this

NB - If we extend the new schema to add additional mandatory fields, we will have to use this workflow again to ensure proper validation (and thus proper updating).

@jachurchill to also create a script that will allow us to extend the new schema with additional mandatory fields.