Implements hook_uninstall().
function forum_uninstall() {
// Load the dependent Taxonomy module, in case it has been disabled.
drupal_load('module', 'taxonomy');
variable_del('node_options_forum');
field_delete_field('taxonomy_forums');
// Purge field data now to allow taxonomy module to be uninstalled
// if this is the only field remaining.
field_purge_batch(10);
}