valve drop=true doesn't allow EOS to flow downstream.

Submitted by Keith Thornton @Keith

Link to original bug (#740432)

Description

The following pipeline hangs after all frames have flowed. This is probably because valve drop=true doesn't pass the EOS event downstream.

gst-launch-1.0.exe -v videotestsrc do-timestamp=true pattern=snow is-live=true num-buffers=90 !video/x-raw,width=1920,height=1080,framerate=30000/1001,format=YV12 ! tee name=t1 ! queue name=displ -queue max-size-bytes=0 leaky=2 ! valve name=display-valve drop=true ! glimagesink sync=false async=false t1. ! queue name=encode-queue max-size-bytes=124416000 ! valve name=encode-valve drop=false ! x264enc bittrate=32768 ! h264parse ! qtmux ! filesink location="f:/temp/out.mp4"