glx: Set ContextTag for all contexts

Currently, xorgGlxMakeCurrent() would set the context tag only for
indirect GLX contexts.

However, several other places expect to find a context for the tag or
they would raise a GLXBadContextTag error, such as WaitGL() or WaitX().

Set the context tag for direct contexts as well, to avoid raising an
error and possibly killing the client.

Thanks to Erik Kurzinger <ekurzinger@nvidia.com> for spotting the issue.

Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
(cherry picked from commit c468d34c)
3 jobs for glx-backports-1.20 in 9 minutes and 31 seconds (queued for 3 seconds)
Status Name Job ID Coverage
  Docker Image
passed debian-testing #10854455

00:00:51

 
  Build And Test
passed autotools-build-and-test #10854456

00:08:40

passed meson-build-and-test #10854457

00:04:53