Contextual link preprocess taxonomy term

gistfile1.php

<?php
/**
 * Preprocess function.
 */
function example_preprocess_taxonomy_term(&$vars) {
  if ($vars['vocabulary_machine_name'] == 'service_category') {
    $contextual_links = array(
      '#type' => 'contextual_links',
      '#contextual_links' => array(
        'taxonomy' => array('taxonomy/term', array($vars['tid'])),
      ),
    );
    $vars['title_suffix']['contextual_links'] = $contextual_links;
  }
}
?>