Do not overwrite the UA_Client logger when using UA_ClientConfig_setDefault

plugins/ua_config_default.c

@@ -683,9 +683,11 @@ UA_ClientConfig_setDefault(UA_ClientConfig *config) {
     config->timeout = 5000;
     config->secureChannelLifeTime = 10 * 60 * 1000; /* 10 minutes */
 
-    config->logger.log = UA_Log_Stdout_log;
-    config->logger.context = NULL;
-    config->logger.clear = UA_Log_Stdout_clear;
+    if(!config->logger.log) {
+       config->logger.log = UA_Log_Stdout_log;
+       config->logger.context = NULL;
+       config->logger.clear = UA_Log_Stdout_clear;
+    }
 
     config->localConnectionConfig = UA_ConnectionConfig_default;