Matthew Waters e0459f1b65 gl: download whenever we have sysmem capsfeatures ...

Otherwise we could pass on a RGBA formatted buffer and downstream would
misinterpret that as some other video format.

Fixes pipelines of the form

    gleffects ! tee ! xvimagesink

2014-09-24 13:16:30 +10:00

..

gl

gl: download whenever we have sysmem capsfeatures

2014-09-24 13:16:30 +10:00