Merge "Explicitly discard released proto strings."

        bp.set_allocated_dest_path(&target);

        bp.set_allocated_source_subdir(&source);

        const auto metadata = bp.SerializeAsString();

        bp.release_dest_path();

        bp.release_source_subdir();

        static_cast<void>(bp.release_dest_path());

        static_cast<void>(bp.release_source_subdir());

        mdFileName = makeBindMdName();

        metadataFullPath = path::join(ifs.root, constants().mount, mdFileName);

        auto node = mIncFs->makeFile(ifs.control, metadataFullPath, 0444, idFromMetadata(metadata),