Merge "fs_mgr: overlay: only use system_<other> if other slot suffix not blank"

        if (!dm.GetDmDevicePathByName(partition_name, &path)) {

            // non-DAP A/B device?

            if (fs_mgr_access(super_device)) return "";

            path = kPhysicalDevice + "system" + (slot_number ? "_a" : "_b");

            auto other_slot = fs_mgr_get_other_slot_suffix();

            if (other_slot.empty()) return "";

            path = kPhysicalDevice + "system" + other_slot;

        }

    }

    return scratch_device_cache = path;