PHP warning issued when the CSS is rebuilt (SASS lib)

git-svn-id: http://svn.code.sf.net/p/itop/code/trunk@3814 a333f486-631f-4898-b8df-5754b55c2be0

lib/sass/sass/script/literals/SassLiteral.php

@@ -355,5 +355,8 @@ abstract class SassLiteral {
 	 * @param string the subject string
 	 * @return mixed match at the start of the string or false if no match
 	 */
-	abstract public static function isa($subject);
+	public static function isa($subject)
+	{
+		return false;
+	}
 }