Now that Drupal core v7.17 supports hook_entity_view() on taxonomy term pages, we can get rid of the metatag_taxonomy_term_view_alter() function that was added in #1700160: Support taxonomy term pages until taxonomy supports hook_entity_view().

Note: Delay this at least one beta release after #1835030: Add documentation & hook_requirements note re Drupal v7.17 is included in a release.