change PYTHON_VERSION back to old value

because MSP patch cannot rename directories, and MSP installed over
the older base would result in immediate crash if Python cannot find
its libs. Version number is hard coded in PYTHONPATH.

Change-Id: Ib90ba3ab6f19a89f1ab2ae6fbc0aad9365d3645d
Bump for 4.0-22

Change-Id: Ie1e528f6a203237818432b182da8e929ccf2e45e