Switch to use -f instead of -F for sendmail (#9961)

Fix #9385

services/mailer/mailer.go

@@ -240,7 +240,7 @@ func (s *sendmailSender) Send(from string, to []string, msg io.WriterTo) error {
 	var closeError error
 	var waitError error
 
-	args := []string{"-F", from, "-i"}
+	args := []string{"-f", from, "-i"}
 	args = append(args, setting.MailService.SendmailArgs...)
 	args = append(args, to...)
 	log.Trace("Sending with: %s %v", setting.MailService.SendmailPath, args)