vaapidecode: don't lost GLTextureUpload on seek
vaapidecode: don't lost GLTextureUpload on seek

When seeking, the decoder is reset, but the buffer pool is not
re-negotiated, but in reset_full() the code forgets if the negotiated buffer
pool has the GLTextureUpload meta.

The decoder knows that GLTextureUpload meta was negotiated in
decide_allocation(), but this method is not called when seeking.

Signed-off-by: Víctor Manuel Jáquez Leal <victorx.jaquez@intel.com>

https://bugzilla.gnome.org/show_bug.cgi?id=752929

ceyusa/gstreamer-vaapi,CapOM/gstreamer-vaapi,01org/iotg-lin-gfx-gstreamer-vaapi,ceyusa/gstreamer-vaapi,CapOM/gstreamer-vaapi,GStreamer/gstreamer-vaapi,GStreamer/gstreamer-vaapi,01org/iotg-lin-gfx-gstreamer-vaapi,01org/iotg-lin-gfx-gstreamer-vaapi,CapOM/gstreamer-vaapi