[hooks/syncschema] do not crash on double removal of a constraint Some complicated migrations may entail a double constraint removal. It is not yet known whether this is a genuine cw bug or the result of a complicated migration story, but we should nevertheless not crash. Rather, emit a CRITICAL warning and proceed. Closes #3595309.

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