mailmap: consistently normalize brian m. carlson's name

v2.18.0-rc0~70^2 (mailmap: update brian m. carlson's email address, 2018-05-08) changed the mailmap to map sandals@crustytoothpaste.ath.cx -> brian m. carlson <sandals@crustytoothpaste.net> instead of sandals@crustytoothpaste.net -> brian m. carlson <sandals@crustytoothpaste.ath.cx> That means the mapping Brian M. Carlson <sandals@crustytoothpaste.ath.cx> -> brian m. carlson <sandals@crustytoothpaste.net> is redundant, so we can remove it. More importantly, it means that the identity "Brian M. Carlson <sandals@crustytoothpaste.net>" used in some commits is not normalized any more. Add a mapping for it. Noticed while updating Debian's Git packaging, which uses "git shortlog --no-merges" to produce a list of changes in each version, grouped by author's (normalized) name. Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>