svga: fix index/vertex buffer surface reference at draw

svga: fix index/vertex buffer surface reference at draw

Currently with the SetVertexBuffers optimization, we avoid emitting
redundant DXSetVertexBuffers commands. However, these buffers surfaces
will still need to be referenced, otherwise, in the case of linux,
the subsequent surface discard map will map to the existing mob instead
of a new one, causing rendering artifacts.

With this patch, we'll call resource_rebind() to reference the resources
even if we are avoiding the actual set command. This fixes the
rendering artifacts in the window title area running with unity in
Ubuntu 14.04

Tested with piglit, glretrace.

Reviewed-by: Brian Paul <brianp@vmware.com>
Reviewed-by: Sinclair Yeh <syeh@vmware.com>