[BSA-093] Security Update for gnutls28

Andreas Metzler uploaded new packages for gnutls28 which fixed the
following security problems:

CVE-2014-1959 / DSA 2866-1 / GNUTLS-SA-2014-1
Suman Jana reported that GnuTLS, deviating from the documented
behavior considers a version 1 intermediate certificate as a CA
certificate by default.

For the testing distribution (jessie) and the unstable distribution
(sid), this problem has been fixed in gnutls26/2.12.23-12 and
gnutls28/3.2.11-1.

For the stable distribution this problem has been fixed in
gnutls26/2.12.20-8.