Add an implementation of PKINIT using NSS instead of OpenSSL, from
nalin@redhat.com.

https://github.com/krb5/krb5/commit/c829ea8c9ac7ac866e6435ba99de90155c3cf144
Commit By: ghudson
Revision: 25327
Changed Files:
U   trunk/src/config/pre.in
U   trunk/src/configure.in
U   trunk/src/plugins/preauth/pkinit/Makefile.in
U   trunk/src/plugins/preauth/pkinit/pkinit.h
U   trunk/src/plugins/preauth/pkinit/pkinit_crypto.h
A   trunk/src/plugins/preauth/pkinit/pkinit_crypto_nss.c
U   trunk/src/plugins/preauth/pkinit/pkinit_identity.c