server session BUGFIX incorrect fopen mode

Fixes #83
diff --git a/src/session_server_ssh.c b/src/session_server_ssh.c
index ff14ae7..ea9bab9 100644
--- a/src/session_server_ssh.c
+++ b/src/session_server_ssh.c
@@ -53,7 +53,7 @@
         return NULL;
     }
 
-    file = fdopen(fd, "r");
+    file = fdopen(fd, "w");
     if (!file) {
         close(fd);
         return NULL;