Removing Shortcodes from Child Theme

Try this out. Remove the already added shortcode then add the new shortcode on the init hook.

function shortcode_cleaner() {
    remove_shortcode( 'entry-twitter-link' ); // Not exactly required
    add_shortcode( 'entry-twitter-link', 'my_remove_shortcode' );
}
add_action( 'init', 'shortcode_cleaner' );

function my_remove_shortcode(){
    return '';
}