Fix issue with index.html pages not loading

we were rejecting empty paths, causing these files to be skipped. How did I miss this?

Author: StrawberryMaster

lib/wayback_machine_downloader.rb

@@ -776,7 +776,8 @@ def setup_logger
 
   # safely sanitize a file id (or id+timestamp)
   def sanitize_and_prepare_id(raw, file_url)
-    return nil if raw.nil? || raw.empty?
+    return nil if raw.nil?
+    return ""  if raw.empty?
     original = raw.dup
     begin
       # work on a binary copy to avoid premature encoding errors