Send mail from the FROM address instead of the login

When SMTP is configured to use a service that doesn't use an email address to log in – e.g. AWS SES or Postmark – the sendmail request fails saying the FROM address is invalid.

cps/helper.py

@@ -176,7 +176,7 @@ def send_raw_email(kindle_mail, msg):
 
         if settings["mail_password"]:
             mailserver.login(settings["mail_login"], settings["mail_password"])
-        mailserver.sendmail(settings["mail_login"], kindle_mail, msg)
+        mailserver.sendmail(settings["mail_from"], kindle_mail, msg)
         mailserver.quit()
 
         smtplib.stderr = org_stderr