CSS: Collapse a double if statement into one

Saves 3 bytes gzipped

Closes gh-2296

src/css/curCSS.js

@@ -17,9 +17,6 @@ function curCSS( elem, name, computed ) {
 	// getPropertyValue is only needed for .css('filter') (#12537)
 	if ( computed ) {
 		ret = computed.getPropertyValue( name ) || computed[ name ];
-	}
-
-	if ( computed ) {
 
 		if ( ret === "" && !jQuery.contains( elem.ownerDocument, elem ) ) {
 			ret = jQuery.style( elem, name );