st/xa: Fix performance regression introduced by commit "Cache render target surface"

The mentioned commit has the nasty side-effect of turning off accelerated
copies.

Cc: "10.1 10.2" <mesa-stable@lists.freedesktop.org>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Jakob Bornecrantz <jakob@vmware.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
(cherry picked from commit 9306b7c171b29ac99f837e9efcd0281caf1d332e)
VERSION: Update to 10.1.3

For the emergency 10.1.3 release.
docs: Add release notes for Mesa 10.1.3.

This is an emergencyt release to make a performance-regression fix available.
docs: Add MD5 sums for 10.1.3

Just after making the release tar files.