libtasn1: security bump to version 4.12

libtasn1: security bump to version 4.12

Fixes CVE-2017-7650: Two errors in the "asn1_find_node()" function
(lib/parser_aux.c) within GnuTLS libtasn1 version 4.10 can be exploited to
cause a stacked-based buffer overflow by tricking a user into processing a
specially crafted assignments file via the e.g.  asn1Coding utility.

For more details, see:

https://secuniaresearch.flexerasoftware.com/secunia_research/2017-11/

Or the 1.4.11 release mail (no mail about 1.4.12, but identical to 1.4.11 +
a soname fix):

https://lists.gnu.org/archive/html/help-libtasn1/2017-05/msg00003.html

Remove 0001-configure-don-t-add-Werror-to-build-flags.patch and autoreconf
as that patch is now upstream.

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>