Don't return data for user 1 when passed in junk like an array. See #13317.

git-svn-id: https://develop.svn.wordpress.org/trunk@14695 602fd350-edb4-49c9-b593-d223f7449a82

wp-includes/pluggable.php

@@ -103,10 +103,13 @@ if ( !function_exists('get_userdata') ) :
 function get_userdata( $user_id ) {
 	global $wpdb;
 
+	if ( ! is_numeric( $user_id ) )
+		return false;
+		
 	$user_id = absint( $user_id );
 	if ( ! $user_id )
 		return false;
-
+	
 	$user = wp_cache_get( $user_id, 'users' );
 
 	if ( $user )