Parsing of runtime env may fail for some legacy installations in full grid mode when running experimental / next

[jonasbardino]

The crash ends up something like:

Traceback (most recent call last):
  File "/home/mig/mig/wsgi-bin/migwsgi.py", line 124, in stub
    (output_objects, (ret_code, ret_msg)) = main(client_id,
  File "/home/mig/mig/shared/functionality/redb.py", line 140, in main
    re_item = build_reitem_object(configuration, re_dict)
  File "/home/mig/mig/shared/refunctions.py", line 399, in build_reitem_object
    created_timetuple = created_timestamp.timetuple()
AttributeError: 'NoneType' object has no attribute 'timetuple'

when a bogus None value is found as CREATED_TIMESTAMP. On edge / main the value is currently not parsed to a date so it just passes as None.

This is the handling for edge / main and needs minor adjustments for the experimental / next branch.

[jonasbardino]

fixed through PR156.