GLX: Free the tag of the old context later

In CommonMakeCurrent() function, the tag of the old context is freed
before the new context is made current. This is problematic because if
the CommonMakeNewCurrent() function fails, the tag of the old context
ends up being removed, even though it is still active. This causes
subsequent glXMakeCurrent() or glXMakeContextCurrent() requests to
generate a GLXBadContextTag error.

This change moves the function call that frees the old tag to a location
where the result of CommonMakeNewCurrent() call is known and it is safe
to free it.

Signed-off-by: Doğukan Korkmaztürk <dkorkmazturk@nvidia.com>
9 jobs for glXMakeCurrentFix in 3 minutes and 36 seconds (queued for 1 second)