fixup! chg: generate, cleanup: Use 28 days of measurements

sbws/config.default.ini

@@ -74,7 +74,7 @@ extra_lines =
 # #40017: To generate files as Torflow the result files must be kept for
 # GENERATE_PERIOD seconds.
 # The number of days after they are compressed or deleted could be added
-# as defaults (currently globals.py), and just as a factor GENERATE_PERIOD.
+# as defaults (currently globals.py), and just as a factor of GENERATE_PERIOD.
 data_files_compress_after_days = 29
 # After this many days, delete data files.
 # 57 == 28 * 2 + 1.