If the script_loader_src filter returns nothing, bail instead of printing <script src="">.

props niallkennedy.
fixes #22470.


git-svn-id: https://develop.svn.wordpress.org/trunk@25465 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/class.wp-scripts.php

@@ -119,6 +119,9 @@ class WP_Scripts extends WP_Dependencies {
 
 		$src = esc_url( apply_filters( 'script_loader_src', $src, $handle ) );
 
+		if ( ! $src )
+			return true;
+
 		if ( $this->do_concat )
 			$this->print_html .= "<script type='text/javascript' src='$src'></script>\n";
 		else