fixup! node-iec61850-goose: Add initial R-GOOSE receiver support

Author: pjungkamp

lib/nodes/iec61850_goose.cpp

@@ -671,8 +671,8 @@ void GooseNode::parseSessionKey(json_t *json) {
   int id;
   char const *security_str;
   char const *signature_str;
-  char const *data_str;
-  char const *data_base64;
+  char const *data_str = nullptr;
+  char const *data_base64 = nullptr;
   ret = json_unpack_ex(json, &err, 0,                   //
                        "{ s:i, s:s, s:s, s:?s, s:?s }", //
                        "id", &id,                       //