face: Fix error message on failed loading attempt

modules/face/src/facerec.cpp

@@ -58,7 +58,7 @@ void FaceRecognizer::load(const String &filename)
 {
     FileStorage fs(filename, FileStorage::READ);
     if (!fs.isOpened())
-        CV_Error(Error::StsError, "File can't be opened for writing!");
+        CV_Error(Error::StsError, "File can't be opened for reading!");
     this->load(fs);
     fs.release();
 }