Remove _handle_win32() method from "create" command class This method generates code in a file using etwist module that we are about to drop.

Skip tests for ldapsource with python >= 3.7 Until someone works on fixing these, this should make our CI green again. I tried to use setupModule() to check for python version, but pre_setup_database() is apparently called even when a SkipTest exception is raised there. So handle this in that method.