Fixes #1856: The default CSS class for hint generated by `ActiveField` is changed to `help-block`

web/css/site.css

@@ -76,12 +76,6 @@ a.desc:after {
     white-space: nowrap;
 }
 
-.hint-block {
-	display: block;
-	margin-top: 5px;
-	color: #999;
-}
-
 .error-summary {
 	color: #a94442;
 	background: #fdf7f7;