Fixed wrong target filename in backup restore

src/DatSubsystems/DatBackupManager.cpp

@@ -72,7 +72,7 @@ namespace LOTRO_DAT {
         std::string dat_filename = dat->GetIO().GetFilename().value;
         dat->Deinitialize();
 
-        FILE* file = fopen(backup_datname.c_str(), "w+b");
+        FILE* file = fopen(dat_filename.c_str(), "w+b");
         if (!file)
             return DatOperationResult<>(ERROR, "RESTOREFROMBACKUP: cannot open file " + backup_datname);