Merged the get_read_fd and get_write_fd requests.

diff --git a/server/semaphore.c b/server/semaphore.c
index 25c0c51..710f6ab 100644
--- a/server/semaphore.c
+++ b/server/semaphore.c
@@ -35,8 +35,7 @@
     semaphore_satisfied,           /* 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 */
     no_get_file_info,              /* get_file_info */
     no_destroy                     /* destroy */