Catch ValueError in formatscaper subprocesses

* these can happen if the error log file gets closed while the
  subprocesses are still writing to it, which can happen if the user
  aborts the execution with ^C

formatscaper/formatscaper.py

@@ -233,7 +233,7 @@ def process_record_file(record_file: RecordFile) -> None:
                 if not args.no_progressbar:
                     progress_bar.update(completed_tasks, force=True)
 
-        except subprocess.CalledProcessError as e:
+        except (subprocess.CalledProcessError, ValueError) as e:
             print("WARN: error during sf execution:", str(e), file=sys.stderr)