Require polarssl >= 1.2.10 for polarssl-builds, which fixes CVE-2013-5915.

PolarSSL 1.2.9 fixes a possible timing attack in PolarSSL's RSA-CRT
implementation. See CVE-2013-5915 for details. This commit bumps the
minimum polarssl version required by configure.ac to 1.2.10, because 1.2.9
also introduced a memory leak, which is fixed in 1.2.10.

Signed-off-by: Steffan Karger <steffan.karger@fox-it.com>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <1382445917-2974-1-git-send-email-steffan.karger@fox-it.com>
URL: http://article.gmane.org/gmane.network.openvpn.devel/7925
Signed-off-by: Gert Doering <gert@greenie.muc.de>
(cherry picked from commit 92d21e3fed33aad966b7b0ca6568e0cda8c7a8b5)