Preliminary fix per code review [skip ci]

lib/import/exchange/folder.rb

@@ -43,7 +43,7 @@ module Import
       end
 
       def display_path(folder)
-        display_name  = folder.display_name.utf8_encode(fallback: :read_as_sanitized_binary)
+        display_name  = folder.display_name.utf8_encode
         parent_folder = find(folder.parent_folder_id)
 
         return display_name if parent_folder.blank?
@@ -51,6 +51,8 @@ module Import
         "#{display_path(parent_folder)} -> #{display_name}"
       rescue Viewpoint::EWS::EwsError
         display_name
+      rescue EncodingError
+        '(undetectable encoding)'
       end
 
       private