vnc-tls: Fix compilation with newer versions of GNU-TLS

In my installation of GNU-TLS (v3.0.23) the type
gnutls_anon_server_credentials is marked deprecated, so -Werror
breaks compilation.
Simply replacing it with the newer ..._t version fixed the compilation
on my machine (Slackware 14.0). I cannot tell how far back this "new"
type goes, at least the header file in RHEL 5.0 (v1.4.1) seems to have
it already. If someone finds a broken distribution, tell me and I
insert some compat code.

Signed-off-by: Andre Przywara <andre.przywara@amd.com>
Message-id: 1350551818-14717-1-git-send-email-andre.przywara@amd.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

ui/vnc-tls.c

diff --git a/ui/vnc-tls.c b/ui/vnc-tls.c
index 5629263..8d4cc8e 100644
--- a/ui/vnc-tls.c
+++ b/ui/vnc-tls.c
@@ -99,9 +99,9 @@
 }
 
 
-static gnutls_anon_server_credentials vnc_tls_initialize_anon_cred(void)
+static gnutls_anon_server_credentials_t vnc_tls_initialize_anon_cred(void)
 {
-    gnutls_anon_server_credentials anon_cred;
+    gnutls_anon_server_credentials_t anon_cred;
     int ret;
 
     if ((ret = gnutls_anon_allocate_server_credentials(&anon_cred)) < 0) {
@@ -382,7 +382,7 @@
             }
 
         } else {
-            gnutls_anon_server_credentials anon_cred = vnc_tls_initialize_anon_cred();
+            gnutls_anon_server_credentials_t anon_cred = vnc_tls_initialize_anon_cred();
             if (!anon_cred) {
                 gnutls_deinit(vs->tls.session);
                 vs->tls.session = NULL;