git-send-email.perl: ensure $domain is defined before using it
git-send-email.perl: ensure $domain is defined before using it

valid_fqdn() may attempt to operate on an undefined value if
Net::Domain::domainname fails to determine the domain name.  This causes
perl to emit unpleasant warnings.

So, add a check for whether $domain has been defined before using it.

Signed-off-by: Brandon Casey <8846602a89ca53d44af0c0033a3c79dc5d05ea84@gmail.com>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git