Add warning if name not found in get_scanner_from_name (UCL#1522)

* Add warning if name not found in get_scanner_from_name

src/buildblock/Scanner.cxx

@@ -2206,6 +2206,7 @@ Scanner::get_scanner_from_name(const string& name)
       type = static_cast<Type>(int_type);
     }
   // it's not in the list
+  warning(std::string("Scanner::get_scanner_from_name: scanner'") + name + "' not found");
   return new Scanner(Unknown_scanner);
 }