send-email: a bit more careful domain regexp.

This tightens the regexp a bit to make sure there is no double dots.

Signed-off-by: Junio C Hamano <junkio@cox.net>

git-send-email.perl

@@ -313,7 +313,7 @@ sub expand_aliases {
 sub extract_valid_address {
 	my $address = shift;
 	my $local_part_regexp = '[^<>"\s@]+';
-	my $domain_regexp = '[^.<>"\s@]+\.[^<>"\s@]+';
+	my $domain_regexp = '[^.<>"\s@]+(?:\.[^.<>"\s@]+)+';
 
 	# check for a local address:
 	return $address if ($address =~ /^($local_part_regexp)$/);