[migractions] remove any session related leftovers Also, the migration handler really wants a "repo" session anyway. This highlights a bug in unittest_wfobjs.test_duplicated_transition where an old connection is reused. It probably used to work because it was made of session + set_cnxset magic dust. Related to #3933480.

#!/usr/bin/env python
from cubicweb.cwctl import run
import sys
run(sys.argv[1:])