vrend: Always use a texture view for the source when doing blits (HACK)

Maybe it's a bug in mesa, maybe I didn't search long enough, but when I
use the source texture directly in the blit then occationally we hit #112,
and no unbinding of the textures from the texture unit or the framebuffers
involved seems to help.
Using a texture view, however, seem to solve the problem.

Fixes #112

Signed-off-by: Gert Wollny <gert.wollny@collabora.com>
Reviewed-by: Gurchetan Singh <gurchetansingh@chromium.org>

src/vrend_renderer.c

@@ -8128,7 +8128,7 @@ static void vrend_renderer_blit_int(struct vrend_context *ctx,
       }
    }
 
-   if ((src_res->base.format != info->src.format) && has_feature(feat_texture_view))
+   if (has_feature(feat_texture_view))
       blitter_views[0] = vrend_make_view(src_res, info->src.format);
 
    if ((dst_res->base.format != info->dst.format) && has_feature(feat_texture_view))