Do not raise warnings for expected headers (#690)

Add expected headers to the allowed_headers method so they do not raise
warnings.

app/importers/curate_mapper.rb

@@ -54,7 +54,7 @@ def initialize(attributes = {})
 
   # What columns are allowed in the CSV
   def self.allowed_headers
-    CURATE_TERMS_MAP.values + ['filename']
+    CURATE_TERMS_MAP.values + ['filename', 'type', 'intermediate_file', 'fileset_label', 'preservation_master_file']
   end
 
   # Given a field name, return the CSV header

spec/system/import_langmuir_from_csv_spec.rb

@@ -50,6 +50,14 @@ def start_import(page)
       expect(page).to have_content(/This import will create or update (17|20) records./)
       # There is a link so the user can cancel.
       expect(page).to have_link 'Cancel', href: '/csv_imports/new?locale=en'
+
+      # We get warnings about unsupported fields
+      expect(page).to have_content('The field name "rights - digitization basis note" is not supported.')
+      expect(page).not_to have_content('The field name "type" is not supported')
+      expect(page).not_to have_content('The field name "intermediate_file" is not supported')
+      expect(page).not_to have_content('The field name "fileset_label" is not supported')
+      expect(page).not_to have_content('The field name "preservation_master_file" is not supported')
+
       # After reading the warnings, the user decides
       # to continue with the import.
       click_on 'Start Import'