Keep machinectl from parsing options of cmd (#56572)

This is needed on machinectl versions prior to v231 (d6c3537ea9 to be precise).

Fixes #56571

lib/ansible/plugins/become/machinectl.py

@@ -84,4 +84,4 @@ class BecomeModule(BecomeBase):
         become = self._get_option('become_exe') or self.name
         flags = self.get_option('flags') or ''
         user = self.get_option('become_user') or ''
-        return '%s shell -q %s %s@ %s' % (become, flags, user, cmd)
+        return '%s shell -q %s %s@ -- %s' % (become, flags, user, cmd)