tls: replace variable in header file with TAILQ_EMPTY()

Use TAILQ_EMPTY to check if a certificate exists instead of
setting two variables in the app-layer-ssl header file for
that purpose only.

src/app-layer-ssl.h

@@ -166,9 +166,6 @@ typedef struct SSLStateConnp_ {
     /* ssl server name indication extension */
     char *sni;
 
-    uint8_t *cert_input;
-    uint32_t cert_input_len;
-
     TAILQ_HEAD(, SSLCertsChain_) certs;
 
     uint32_t cert_log_flag;

src/log-tlsstore.c

@@ -105,7 +105,7 @@ static void LogTlsLogPem(LogTlsStoreLogThread *aft, const Packet *p, SSLState *s
     uint8_t *ptmp;
     SSLCertsChain *cert;
 
-    if ((state->server_connp.cert_input == NULL) || (state->server_connp.cert_input_len == 0))
+    if (TAILQ_EMPTY(&state->server_connp.certs))
         SCReturn;
 
     CreateFileName(p, state, filename);

src/output-json-tls.c

@@ -244,8 +244,7 @@ static void JsonTlsLogJa3(json_t *js, SSLState *ssl_state)
 
 static void JsonTlsLogCertificate(json_t *js, SSLState *ssl_state)
 {
-    if ((ssl_state->server_connp.cert_input == NULL) ||
-            (ssl_state->server_connp.cert_input_len == 0)) {
+    if (TAILQ_EMPTY(&ssl_state->server_connp.certs)) {
         return;
     }
 
@@ -264,8 +263,7 @@ static void JsonTlsLogCertificate(json_t *js, SSLState *ssl_state)
 
 static void JsonTlsLogChain(json_t *js, SSLState *ssl_state)
 {
-    if ((ssl_state->server_connp.cert_input == NULL) ||
-            (ssl_state->server_connp.cert_input_len == 0)) {
+    if (TAILQ_EMPTY(&ssl_state->server_connp.certs)) {
         return;
     }