glx: Do not advertise buffer_age on dri2

glx: Do not advertise buffer_age on dri2

Previously GLX_EXT_buffer_age has always been advertised as supported because
both client_glx_support and client_glx_only where set. So it did not matter
that direct_support is only set when running dri3 and we ended up always
advertising it.

Fix that by not setting client_glx_only for buffer_age in known_glx_extensions.

Signed-off-by: Adel Gadllah <adel.gadllah@gmail.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>