Badly indented code

[Chris Graham]

Very minor but worth fixing…

    } else {
        assert(index >= 0);
        if (zip_file_replace(z, static_cast<zip_uint64_t>(index), s, ZIP_FL_ENC_GUESS) < 0) {
        delete cbs;
        zip_source_free(s);
        return -ENOMEM;
    }
    }

[Alexander Galanin]

fix indentation, closes issue #61

→ <<cset 3afdc577a90c>>