ssl: deprecate CURLE_SSL_CACERT in favour of a unified error code

Long live CURLE_PEER_FAILED_VERIFICATION

lib/strerror.c

@@ -191,9 +191,6 @@ curl_easy_strerror(CURLcode error)
   case CURLE_TELNET_OPTION_SYNTAX :
     return "Malformed telnet option";
 
-  case CURLE_PEER_FAILED_VERIFICATION:
-    return "SSL peer certificate or SSH remote key was not OK";
-
   case CURLE_GOT_NOTHING:
     return "Server returned nothing (no headers, no data)";
 
@@ -218,9 +215,8 @@ curl_easy_strerror(CURLcode error)
   case CURLE_SSL_CIPHER:
     return "Couldn't use specified SSL cipher";
 
-  case CURLE_SSL_CACERT:
-    return "Peer certificate cannot be authenticated with given CA "
-      "certificates";
+  case CURLE_PEER_FAILED_VERIFICATION:
+    return "SSL peer certificate or SSH remote key was not OK";
 
   case CURLE_SSL_CACERT_BADFILE:
     return "Problem with the SSL CA cert (path? access rights?)";
@@ -324,6 +320,7 @@ curl_easy_strerror(CURLcode error)
   case CURLE_OBSOLETE44:
   case CURLE_OBSOLETE46:
   case CURLE_OBSOLETE50:
+  case CURLE_OBSOLETE51:
   case CURLE_OBSOLETE57:
   case CURL_LAST:
     break;

lib/vtls/darwinssl.c

@@ -2099,7 +2099,7 @@ static int append_cert_to_array(struct Curl_easy *data,
     switch(result) {
       case CURLE_OK:
         break;
-      case CURLE_SSL_CACERT:
+      case CURLE_PEER_FAILED_VERIFICATION:
         return CURLE_SSL_CACERT_BADFILE;
       case CURLE_OUT_OF_MEMORY:
       default:

lib/vtls/nss.c

@@ -1522,7 +1522,6 @@ static bool is_nss_error(CURLcode err)
 {
   switch(err) {
   case CURLE_PEER_FAILED_VERIFICATION:
-  case CURLE_SSL_CACERT:
   case CURLE_SSL_CERTPROBLEM:
   case CURLE_SSL_CONNECT_ERROR:
   case CURLE_SSL_ISSUER_ERROR: