Revert "Add flag to obs_source_frame for unbuffered video"

This reverts commit c3f4b0f018.

The obs_source_frame should not need to take flags to do this.  This
shouldn't be a setting associated with the frame, but rather a setting
associated with the source itself.  This was the wrong approach to
solving this particular problem.

plugins/win-dshow/win-dshow.cpp

@@ -377,7 +377,6 @@ void DShowInput::OnEncodedVideoData(enum AVCodecID id,
 
 	if (got_output) {
 		frame.timestamp = (uint64_t)ts * 100;
-		frame.flags = 0;
 #if LOG_ENCODED_VIDEO_TS
 		blog(LOG_DEBUG, "video ts: %llu", frame.timestamp);
 #endif
@@ -398,7 +397,6 @@ void DShowInput::OnVideoData(const VideoConfig &config,
 	const int cy = config.cy;
 
 	frame.timestamp  = (uint64_t)startTime * 100;
-	frame.flags      = 0;
 	frame.width      = config.cx;
 	frame.height     = config.cy;
 	frame.format     = ConvertVideoFormat(config.format);