server: Fix the handling of the signaled status for file descriptors.
    
File handles are signaled when an I/O operation completes, and reset
when another operation is queued.
diff --git a/server/serial.c b/server/serial.c
index f2b88c1..8dc1d18 100644
--- a/server/serial.c
+++ b/server/serial.c
@@ -89,8 +89,8 @@
 {
     sizeof(struct serial),        /* size */
     serial_dump,                  /* dump */
-    default_fd_add_queue,         /* add_queue */
-    default_fd_remove_queue,      /* remove_queue */
+    add_queue,                    /* add_queue */
+    remove_queue,                 /* remove_queue */
     default_fd_signaled,          /* signaled */
     no_satisfied,                 /* satisfied */
     no_signal,                    /* signal */