ensure timeout error is shown on u2f timeout (#14417)

Signed-off-by: Andrew Thornton <art27@cantab.net>

templates/user/auth/u2f_error.tmpl

 			<div class="hide" id="u2f-error-4">
 			{{.i18n.Tr "u2f_error_4"}}
 			</div>
-			<div class="hide u2f-error-5">
+			<div class="hide u2f_error_5">
 			{{.i18n.Tr "u2f_error_5"}}
 			</div>
 		</div>

web_src/js/index.js

     2: $('#u2f-error-2'),
     3: $('#u2f-error-3'),
     4: $('#u2f-error-4'),
-    5: $('.u2f-error-5')
+    5: $('.u2f_error_5')
   };
   u2fErrors[errorType].removeClass('hide');