logind: fix taking of inhibitors

Ooops made in 0a9bf7fa59.

src/login/logind-dbus.c

@@ -3299,6 +3299,7 @@ static int method_inhibit(sd_bus_message *message, void *userdata, sd_bus_error
         r = inhibitor_start(i);
         if (r < 0)
                 return r;
+        TAKE_PTR(i);
 
         return sd_bus_reply_method_return(message, "h", fifo_fd);
 }