opengl: Backed out hg changeset 0c915d307499

This is the OpenGL line drawing fix for Bugzilla #3182, but there's some
disagreement about what the renderers should do here, so I'm backing this out
until after 2.0.12 ships, and then we'll reevaluate all the renderer backends
to decide what's correct, and make them all work the same.
3 files changed