vrend: assume gl_colorspace also when no context type is set

when virgl_renderer_init is called from qemu for initializing D-GL no context type flags are set and the context remains at NONE. Assume in this case that gl_colorspace is true, otherwise the feat_srgb_write_control flag will be cleared and the guest only gets OpenGL 2.1 compatibility.

Signed-off-by: Gert Wollny gert.wollny@collabora.com