Merged the get_read_fd and get_write_fd requests.

diff --git a/server/device.c b/server/device.c
index f1ab4c3..4183b75 100644
--- a/server/device.c
+++ b/server/device.c
@@ -41,8 +41,7 @@
     NULL,                     /* satisfied */
     NULL,                     /* get_poll_events */
     NULL,                     /* poll_event */
-    no_read_fd,               /* get_read_fd */
-    no_write_fd,              /* get_write_fd */
+    no_get_fd,                /* get_fd */
     no_flush,                 /* flush */
     device_get_info,          /* get_file_info */
     no_destroy                /* destroy */