Fix JSHint errors in custom-header.js and custom-background.js.

props jorbin.
fixes #25915, #25916.

Built from https://develop.svn.wordpress.org/trunk@26158


git-svn-id: http://core.svn.wordpress.org/trunk@26069 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/js/custom-background.js

@@ -1,7 +1,8 @@
+/* global ajaxurl */
 (function($) {
 	$(document).ready(function() {
-		var bgImage = $("#custom-background-image"),
-			frame;
+		var frame,
+			bgImage = $( '#custom-background-image' );
 
 		$('#background-color').wpColorPicker({
 			change: function( event, ui ) {
@@ -71,4 +72,4 @@
 			frame.open();
 		});
 	});
-})(jQuery);
+})(jQuery);

wp-admin/js/custom-header.js

@@ -1,3 +1,4 @@
+/* global isRtl */
 (function($) {
 	var frame;