Merge "[qemu]: Fix payload size format in qemu_pipe_frame_send()"

                                           const void* buff,

                                           size_t len) {

    char header[5];

    snprintf(header, sizeof(header), "%04zu", len);

    snprintf(header, sizeof(header), "%04zx", len);

    ssize_t ret = TEMP_FAILURE_RETRY(write(fd, header, 4));

    if (ret != 4) {

        QEMU_PIPE_DEBUG("Can't write qemud frame header: %s", strerror(errno));