dri_interface: Update __DRItexBufferExtensionRec to version 3

With commit e59fa4c46c8("dri2: release texture image.") we updated the
extension without bumping the version number. The patch itself added an
interface required to enable texture_from_pixmap on certain platforms.

The new code was effectively never build, as it depended on
__DRI_TEX_BUFFER_VERSION >= 3, which never came to be in upstream mesa.

This commit bumps the version number, drops the __DRI_TEX_BUFFER_VERSION
checks and resolves all the build conflicts. Additionally it add a version
check as egl and dri3, as require version 2 of the extension which does
not have the releaseTexBuffer hook.

Cc: Juan Zhao <juan.j.zhao@intel.com>
Cc: Kristian Høgsberg <krh@bitplanet.net>
Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Kristian Høgsberg <krh@bitplanet.net>

src/glx/dri3_glx.c

@@ -1527,7 +1527,8 @@ dri3_release_tex_image(Display * dpy, GLXDrawable drawable, int buffer)
    if (pdraw != NULL) {
       psc = (struct dri3_screen *) base->psc;
 
-      if (psc->texBuffer->releaseTexBuffer)
+      if (psc->texBuffer->base.version >= 3 &&
+          psc->texBuffer->releaseTexBuffer != NULL)
          (*psc->texBuffer->releaseTexBuffer) (pcp->driContext,
                                               pdraw->base.textureTarget,
                                               pdraw->driDrawable);