Merge branch 'sa/send-email-smtp-batch-data-limit' into maint

When "git send-email" wanted to talk over Net::SMTP::SSL, Net::Cmd::datasend() did not like to be fed too many bytes at the same time and failed to send messages. Send the payload one line at a time to work around the problem. * sa/send-email-smtp-batch-data-limit: git-send-email.perl: Fixed sending of many/huge changes/patches