Fix recording exception

[lywxs]

In the 32bit Windows7 system， when recording or pause, insert a new device that needs to be installed and driven, soundio exception

32位 Win7（也许64位也会有），录音中或者是暂停录音，也就是设备没有释放的时候，插入需要安装驱动的音频设备，soundio崩溃。

fix code：
rd.prop_variant_value_inited = true;
if (FAILED(hr = IPropertyStore_GetValue(rd.prop_store,PKEY_AUDIOENGINE_DEVICEFORMAT, &rd.prop_variant_value)))
{
rd.device_shared->probe_error = SoundIoErrorOpeningDevice;
rd.device_raw->probe_error = SoundIoErrorOpeningDevice;
rd.device_shared = NULL;
rd.device_raw = NULL;
continue;
}
// add by liangyaowei
if (rd.prop_variant_value.blob.cbSize == 0) {
rd.device_shared->probe_error = SoundIoErrorOpeningDevice;
rd.device_raw->probe_error = SoundIoErrorOpeningDevice;
rd.device_shared = NULL;
rd.device_raw = NULL;
continue;
}
// end

    WAVEFORMATEXTENSIBLE *valid_wave_format = (WAVEFORMATEXTENSIBLE *)rd.prop_variant_value.blob.pBlobData;
    if (valid_wave_format->Format.wFormatTag != WAVE_FORMAT_EXTENSIBLE) {