This is the last version supporting python 2.7.

See merge request nexedi/slapos!1428

This reverts commit 31eaaec1a2bd8bc8648a686a83be989a9615a93e.

This slows down business template by a factor of two and it seems we
don't need it. I'm experimenting with hacks in ppml.py but maybe just
creating the Unpickler with encoding='utf-8' in
product/ERP5Type/XMLExportImport/__init__.py:267 is enough ?

at this point they all fail after long timeouts, because neo does not
support py3 yet

Not sure why it was OK on python2 and not sure if this has to be done
or the promise code needs to cast the results of getConfig()

Otherwise it fails with the following exception because of non-ASCII characters
(`[A-Z&é@{]{3,7})`) (see unconvert()) below):

  => erp5_core/PathTemplateItem/portal_preferences/default_site_preference.xml
     File "zodbpickle-2.0.0-py3.7-linux-x86_64.egg/zodbpickle/pickle_3.py", line 844, in load
        dispatch[key[0]](self)
     File "zodbpickle-2.0.0-py3.7-linux-x86_64.egg/zodbpickle/pickle_3.py", line 1035, in load_short_binstring
        self.append(self.decode_string(data))
     File "zodbpickle-2.0.0-py3.7-linux-x86_64.egg/zodbpickle/pickle_3.py", line 989, in decode_string
        return value.decode(self.encoding, self.errors)
  UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position 19: ordinal not in range(128)

This reverts commit 6c399134.

See merge request nexedi/slapos!1404