vrend: lie a bit about the number of available UBOs
When the host reports 14 UBOs supported, the guest will only see support for 13 UBOs which is one short of the number required to expose ARB_uniform_buffer_objects, and with this extension disabled, we will only support OpenGL 3.0 in the guest.
To support higher OpenGL versions in the guest, lie about the number of available UBOs, i.e. report 15 UBOs to the guest.
Related: #286 (closed) Signed-off-by: Gert Wollny gert.wollny@collabora.com