tests: stop worrying about obsolete environment variables After v0.99.7~99 (Retire support for old environment variables, 2005-09-09), there is no more need to unset a stray AUTHOR_NAME variable that might have entered the test environment. Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>