[ERROR   ] An un-handled exception was caught by salt's global exception handler:
TypeError: argument of type 'NoneType' is not iterable
Traceback (most recent call last):
  File "/usr/bin/salt-minion", line 14, in <module>
    salt_minion()
  File "/usr/lib/pymodules/python2.7/salt/scripts.py", line 30, in salt_minion
    minion.start()
  File "/usr/lib/pymodules/python2.7/salt/__init__.py", line 219, in start
    self.prepare()
  File "/usr/lib/pymodules/python2.7/salt/__init__.py", line 207, in prepare
    self.minion = salt.minion.Minion(self.config)
  File "/usr/lib/pymodules/python2.7/salt/minion.py", line 514, in __init__
    self.returners)
  File "/usr/lib/pymodules/python2.7/salt/utils/schedule.py", line 69, in __init__
    clean_proc_dir(opts)
  File "/usr/lib/pymodules/python2.7/salt/utils/schedule.py", line 259, in clean_proc_dir
    if 'pid' in job:
TypeError: argument of type 'NoneType' is not iterable
Traceback (most recent call last):
  File "/usr/bin/salt-minion", line 14, in <module>
    salt_minion()
  File "/usr/lib/pymodules/python2.7/salt/scripts.py", line 30, in salt_minion
    minion.start()
  File "/usr/lib/pymodules/python2.7/salt/__init__.py", line 219, in start
    self.prepare()
  File "/usr/lib/pymodules/python2.7/salt/__init__.py", line 207, in prepare
    self.minion = salt.minion.Minion(self.config)
  File "/usr/lib/pymodules/python2.7/salt/minion.py", line 514, in __init__
    self.returners)
  File "/usr/lib/pymodules/python2.7/salt/utils/schedule.py", line 69, in __init__
    clean_proc_dir(opts)
  File "/usr/lib/pymodules/python2.7/salt/utils/schedule.py", line 259, in clean_proc_dir
    if 'pid' in job:
TypeError: argument of type 'NoneType' is not iterable