UKLP harvesters returning errors when importing due to schema changes

[amercader]

See trace below.

There are two issues here:

1. As in #2231, the schema passed with the context is no longer used on the logic layer (in this case the one used on the DGU form is used). This can be fixed allowing a schema to be passed with the context.

2. Datasets created via the harvesting (UKLP ones) and the ones created via the form use a different schema. That could lead to problems. We need to discuss the best approach.

  File "/var/lib/ckan/std/pyenv/src/ckanext-inspire/ckanext/inspire/harvesters.py", line 139, in import_stage
    self.import_gemini_object(harvest_object.content)
  File "/var/lib/ckan/std/pyenv/src/ckanext-inspire/ckanext/inspire/harvesters.py", line 163, in import_gemini_object
    package = self.write_package_from_gemini_string(unicode_gemini_string)
  File "/var/lib/ckan/std/pyenv/src/ckanext-inspire/ckanext/inspire/harvesters.py", line 386, in write_package_from_gemin
    package = self._create_package_from_data(package_dict, package = package)
  File "/var/lib/ckan/std/pyenv/src/ckanext-inspire/ckanext/inspire/harvesters.py", line 486, in _create_package_from_dat
    package_dict = action_function(context, package_dict)
  File "/usr/lib/pymodules/python2.6/ckan/logic/action/update.py", line 169, in package_update
    data, errors = validate(data_dict, schema, context)
  File "/usr/lib/pymodules/python2.6/ckan/lib/navl/dictization_functions.py", line 216, in validate
    converted_data, errors = _validate(flattened, schema, context)
  File "/usr/lib/pymodules/python2.6/ckan/lib/navl/dictization_functions.py", line 289, in _validate
    convert(converter, key, converted_data, errors, context)
  File "/usr/lib/pymodules/python2.6/ckan/lib/navl/dictization_functions.py", line 179, in convert
    converter(key, converted_data, errors, context)
  File "/var/lib/ckan/std/pyenv/src/ckanext-dgu/ckanext/dgu/validators.py", line 81, in validate_license
    if data[('license_id',)]== '__extra__':
KeyError: ('access_constraints',)
2012-03-19 10:47:41,736 ERROR [ckanext.inspire.harvesters] Error importing Gemini document: ('access_constraints',)