streaming: Handle and recover from GStreamer encoding errors
streaming: Handle and recover from GStreamer encoding errors

If an error occurs for whatever reason (e.g. codec not supporting odd
frame sizes), the GStreamer pipeline will drop the current buffer,
causing the encoder to be stuck waiting for the sample. So this patch
tracks error notifications and ensures we don't wait for a sample if
none will come.

Signed-off-by: Francois Gouget <6b915da68578f6eb004fe99432b967565fc9be8f@codeweavers.com>

fgouget/spice,fgouget/spice,fgouget/spice,fgouget/spice