Removes CTLOG_new_null from the CT public API

This is an entirely useless function, given that CTLOG is publicly
immutable.
Reviewed-by: NMatt Caswell <matt@openssl.org>
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/1406)

crypto/ct/ct_err.c

@@ -22,7 +22,6 @@ static ERR_STRING_DATA CT_str_functs[] = {
     {ERR_FUNC(CT_F_CTLOG_NEW), "CTLOG_new"},
     {ERR_FUNC(CT_F_CTLOG_NEW_FROM_BASE64), "CTLOG_new_from_base64"},
     {ERR_FUNC(CT_F_CTLOG_NEW_FROM_CONF), "ctlog_new_from_conf"},
-    {ERR_FUNC(CT_F_CTLOG_NEW_NULL), "CTLOG_new_null"},
     {ERR_FUNC(CT_F_CTLOG_STORE_LOAD_CTX_NEW), "ctlog_store_load_ctx_new"},
     {ERR_FUNC(CT_F_CTLOG_STORE_LOAD_FILE), "CTLOG_STORE_load_file"},
     {ERR_FUNC(CT_F_CTLOG_STORE_LOAD_LOG), "ctlog_store_load_log"},

crypto/ct/ct_log.c

@@ -234,10 +234,12 @@ end:
  */
 CTLOG *CTLOG_new(EVP_PKEY *public_key, const char *name)
 {
-    CTLOG *ret = CTLOG_new_null();
+    CTLOG *ret = OPENSSL_zalloc(sizeof(*ret));
 
-    if (ret == NULL)
+    if (ret == NULL) {
+        CTerr(CT_F_CTLOG_NEW, ERR_R_MALLOC_FAILURE);
         return NULL;
+    }
 
     ret->name = OPENSSL_strdup(name);
     if (ret->name == NULL) {
@@ -255,16 +257,6 @@ err:
     return NULL;
 }
 
-CTLOG *CTLOG_new_null(void)
-{
-    CTLOG *ret = OPENSSL_zalloc(sizeof(*ret));
-
-    if (ret == NULL)
-        CTerr(CT_F_CTLOG_NEW_NULL, ERR_R_MALLOC_FAILURE);
-
-    return ret;
-}
-
 /* Frees CT log and associated structures */
 void CTLOG_free(CTLOG *log)
 {

include/openssl/ct.h

@@ -412,12 +412,6 @@ __owur int o2i_SCT_signature(SCT *sct, const unsigned char **in, size_t len);
  */
 CTLOG *CTLOG_new(EVP_PKEY *public_key, const char *name);
 
-/*
- * Creates a new, blank CT log instance.
- * Should be deleted by the caller using CTLOG_free when no longer needed.
- */
-CTLOG *CTLOG_new_null(void);
-
 /*
  * Creates a new CT |ct_log| instance with the given base64 public_key and |name|.
  * Should be deleted by the caller using CTLOG_free when no longer needed.