With the previous code, an alias cycle like:
$ echo 'alias a b' >aliases
$ echo 'alias b a' >aliases
$ git config sendemail.aliasesfile aliases
$ git config sendemail.aliasfiletype mutt
would put send-email into an infinite loop. This patch
detects the situation and complains to the user.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>