fix flake 8 errors for CMS 

 
23:01:32 style runtests: PYTHONHASHSEED='3418957794'23:01:32 style runtests: commands[0] | flake8*23:01:32* ./django/cms/migrations/0002_user_application.py:65:5: E722 do not use bare except'23:01:32 except:23:01:32 ^23:01:32 ./django/cms/migrations/0002_user_application.py:80:5: E722 do not use bare except'23:01:32 except:23:01:32 ^23:01:32 ERROR: InvocationError: '/w/workspace/vvp-cms-master-validation-scripts-verify-python/.tox/style/bin/flake8'