jeffersonpowers on "Changes to core files to improve SEO?"

Apologies if some of this is vague. A client of a client is complaining about Google Analytics errors on his web page, specifically that he's getting "missing: author" and "missing: updated" errors, which he thinks is disrupting his search placement.

The client went to a programmer, who made the following changes to the WordPress core files (bad idea, I know):

#1. In wp-settings.php, swapped places of following line:

require( ABSPATH . WPINC . '/plugin.php' );
require( ABSPATH . WPINC . '/functions.php' );

Earlier functions.php was above plugin.php

#2. In functions.php, added following code:

add_filter( 'post_class', 'remove_hentry_function', 20 );
function remove_hentry_function( $classes ) {
    if( ( $key = array_search( 'hentry', $classes ) ) !== false )
        unset( $classes[$key] );
    return $classes;
}

I'm not a PHP programmer so I don't really know what this is even supposed to do. I need to know if there is a way to implement his solution without editing the core files, or a better way to get rid of the Google Analytics errors, via a plugin or theme function.

I would appreciate any help or advice. Thank you.