Update send_mail.md

troubleshooting/send_mail.md

 # Envoi de mails
 
+
+/var/spool/
+
+```bash
+root@MaarchIntegration1904:/var/spool/mail# ls -ltr
+total 4
+-rw------- 1 root mail    0 sept. 25  2018 root
+-rw------- 1 mail mail 1888 sept. 25  2018 maarch
+
+```
+
+
 contexte
 
 notif_email_stack (table vider les dates creation date et send date)