[Piuparts-reports] daily report, manually triggered on pejacevic for the 8th time

[piuparts master]

Traceback (most recent call last):
  File "/srv/piuparts.debian.org/share/piuparts/master/detect_well_known_errors", line 557, in <module>
    detect_well_known_errors( conf, problem_list, False, False )
  File "/srv/piuparts.debian.org/share/piuparts/master/detect_well_known_errors", line 521, in detect_well_known_errors
    recheck, recheck_failed )
TypeError: 'NoneType' object is not iterable