XML-RPC: Include 'sticky' in the struct returned from metaWeblog.getRecentPosts.

Using wp.getPosts is preferred and non-WP XML-RPC APIs are no longer actively maintained. This is simply for parity with existing MW methods.

props soulseekah.
fixes #26679.

Built from https://develop.svn.wordpress.org/trunk@27553


git-svn-id: http://core.svn.wordpress.org/trunk@27396 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/class-wp-xmlrpc-server.php

@@ -4846,7 +4846,8 @@ class wp_xmlrpc_server extends IXR_Server {
 				'custom_fields' => $this->get_custom_fields($entry['ID']),
 				'wp_post_format' => $post_format,
 				'date_modified' => $post_modified,
-				'date_modified_gmt' => $post_modified_gmt
+				'date_modified_gmt' => $post_modified_gmt,
+				'sticky' => ( $entry['post_type'] === 'post' && is_sticky( $entry['ID'] ) ),
 			);
 
 			$entry_index = count( $struct ) - 1;