Rename test and update the test description to explicitly state that
included tests all relate to commit authorship. The t7509-commit.sh
file was not renamed when other scripts were updated in compliance
with the test naming convention.
[1] f50c9f76c ("Rename some test scripts and describe the naming convention", 2005-05-15)
Signed-off-by: Stephen P. Smith <ischis2@cox.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
