Import local translations when enabling a module.

myprofile.profile

<?php

/**
 * Implements hook_modules_enabled().
 *
 * Install translations for all modules.
 */
function myprofile_modules_enabled($modules) {
  $langs = language_list();
  // For each enabled module.
  foreach ($modules as $module) {
    $translations_dir = DRUPAL_ROOT . '/' . drupal_get_path('module', $module) . '/translations';
    // For each enabled language.
    foreach ($langs as $lang => $language) {
      // Try to find the translations file that can be named
      // - LANG.po
      // - MODULE.LANG.po
      $path = $translations_dir . '/' . $lang . '.po';
      if (!file_exists($path)) {
        $path = $translations_dir . '/' . $module . '.' . $lang . '.po';
      }
      // If the translation file exists.
      if (file_exists($path)) {
        // Load the file managed object from the database.
        $file = reset(file_load_multiple(array(), array('uri' => $path)));
        // If that file has never been managed, do it now.
        if (empty($file)) {
          $file = new stdClass();
          $file->fid = NULL;
          $file->original = NULL;
          $file->uri = $path;
          file_save($file);
        }
        // Process import.
        _locale_import_po($file, $lang, LOCALE_IMPORT_OVERWRITE, 'default');
      }
    }
  }
}