Blender Git Loki

OpenGL render: Update metadata as before, for every frame written to a
file, since we need the updated times and frames.

This was lost during stamp code refactoring. The refactoring moved the
stamp when render is initialized so we would be guaranteed to have
correct cameras even when saving render stills at a later time (and even
if cameras were changed). For regular render this would work since
render init takes care of stamp, but for openGL rendering we need to do
this manually.

Still not 100% correct, does not apply multiview cameras to metadata