Fix infinite recursion

[psavery]

We need to move the logic for fixing the deserialization of a polar distortion object into HexrdConfig, which might not be fully constructed yet, to avoid an infinite recursion.

[pep8speaks]

Hello @psavery! Thanks for opening this PR. We checked the lines you've touched for PEP 8 issues, and found:

• In the file hexrdgui/hexrd_config.py:

Line 2431:80: E501 line too long (80 > 79 characters) Line 2434:80: E501 line too long (84 > 79 characters)