White frames with v4l2 source & GstGLUploadElement

[Gottfried Haider]

> V4L2src does not have any relationship with GL. The element that does
> the upload is called glupload. What is likely your issue, is that
> someone broke older GLES support while adding version 3 support. Can
> you reproduce with simple pipeline like ?

Will test tomorrow morning!

What I meant: I was expecting the testegl code to handle the uploading
of the buffer, since it is clearly written to do exactly that. So I
found it curious that the "raw image" already shows up at the callback
for the "handoff" signal as a GLMemory.

Thanks!
Gottfried