Copy name to tr->dictionary_name if not equal

This is a similar change to b60d2452c3.
In this case, it is when tr->dictionary_name is passed as the name
parameter in LoadDictionary.

This happens in the SetTranslator2 function when loading the
dictionary for the second language translator object.

src/libespeak-ng/dictionary.c

@@ -214,7 +214,8 @@ int LoadDictionary(Translator *tr, const char *name, int no_error)
 
 	if (dictionary_name != name)
 		strncpy(dictionary_name, name, 40); // currently loaded dictionary name
-	strncpy(tr->dictionary_name, name, 40);
+	if (tr->dictionary_name != name)
+		strncpy(tr->dictionary_name, name, 40);
 
 	// Load a pronunciation data file into memory
 	// bytes 0-3:  offset to rules data