Added the possibility to use dts time stamp if pts is missing.

 For mkv container media we sometimes did had a dts timestamp
 but no pts timestamp by converted media. Now even if the media is
 not dts audio but has a dts timestamp and not a pts time stamp the dts
 time stamp will be used. This looks to be needed for all gstreamer
 versions above 1.5.1 . It is in experimental. At first it does not seem
 to break anything but needs more testing. By me it only improved
 media support.

	modified:   gstdvbvideosink.c

gstdvbvideosink.c

@@ -1001,7 +1001,7 @@ static GstFlowReturn gst_dvbvideosink_render(GstBaseSink *sink, GstBuffer *buffe
 		}
 	}
 
-	if (GST_BUFFER_PTS_IS_VALID(buffer) || (self->use_dts && GST_BUFFER_DTS_IS_VALID(buffer)))
+	if (GST_BUFFER_PTS_IS_VALID(buffer) || GST_BUFFER_DTS_IS_VALID(buffer))
 	{
 		pes_header[7] = 0x80; /* pts */
 		pes_header[8] = 5; /* pts size */