[Mesa-stable] Request for stable inclusion

[Ilia Mirkin]

Please add to the 10.5 and 10.6 release branches the following commit.
I got confirmation from the original reporter that it fixed his
issues.

>From aba3392541f38f82e3ebde251fdcca78e90adbf3 Mon Sep 17 00:00:00 2001
From: Ilia Mirkin <imirkin at alum.mit.edu>
Date: Thu, 5 Mar 2015 12:10:15 -0500
Subject: nv30: avoid doing extra work on clear and hitting unexpected states

Clearing can happen at a time when various state objects are incoherent
and not ready for a draw. Some of the validation functions don't handle
this well, so only flush the framebuffer state. This has the advantage
of also not doing extra work.

This works around some crashes that can happen when clearing.

Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
Reviewed-by: Tobias Klausmann <tobias.johannes.klausmann at mni.thm.de>