Minor fix

@@ -44,10 +44,10 @@ imap4d_delete (struct imap4d_session *session,
   if (!name || *name == '\0')
     return io_completion_response (command, RESP_BAD, "Too few arguments");
 
-  /* It is an error to attempt to delele "INBOX or a mailbox
-     name that dos not exists.  */
+  /* It is an error to attempt to delele "INBOX" or a mailbox
+     name that does not exist.  */
   if (mu_c_strcasecmp (name, "INBOX") == 0)
-    return io_completion_response (command, RESP_NO, "Already exist");
+    return io_completion_response (command, RESP_NO, "Cannot remove");
 
   /* Allocates memory.  */
   name = namespace_get_name (name, &record, NULL);