eo_mailbox: skip servers where dovecot is installed (#50374)

prometheus-entrouvert-exporter/prometheus-entrouvert-exporter.py

@@ -127,6 +127,10 @@ def packages(ctn):
 
 
 def mailboxes(ctn):
+    if os.path.exists('/etc/dovecot/dovecot.conf'):
+        # skip servers where dovecot is installed as it's expected to have
+        # mailboxes there.
+        return
     boxes = glob.glob("/var/spool/mail/*")
     for m in boxes:
         if os.path.isfile(m):