lib/vty: register vtysh socket in server socket vector (BZ#754)

Register the vtysh socket in Vvty_serv_thread so it will be
correctly closed on vty_reset instead of being leaked.

Signed-off-by: Christian Franke <chris@opensourcerouting.org>
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
diff --git a/lib/vty.c b/lib/vty.c
index 70bf564..0d6345c 100644
--- a/lib/vty.c
+++ b/lib/vty.c
@@ -71,7 +71,7 @@
 static char *vty_ipv6_accesslist_name = NULL;
 
 /* VTY server thread. */
-vector Vvty_serv_thread;
+static vector Vvty_serv_thread;
 
 /* Current directory. */
 char *vty_cwd = NULL;
@@ -2509,7 +2509,8 @@
       break;
 #ifdef VTYSH
     case VTYSH_SERV:
-      thread_add_read (master, vtysh_accept, vty, sock);
+      vty_serv_thread = thread_add_read (master, vtysh_accept, vty, sock);
+      vector_set_index (Vvty_serv_thread, sock, vty_serv_thread);
       break;
     case VTYSH_READ:
       vty->t_read = thread_add_read (master, vtysh_read, vty, sock);