Revert "lib: address -Wunused-but-set-variable"

Stephen Hemminger's commits contain all the changes and
several other warning fixes.

This reverts commit 6947dbebdc91b6272f8107a6e0dd211457438606.
diff --git a/lib/vty.c b/lib/vty.c
index 83bd678..d9eb921 100644
--- a/lib/vty.c
+++ b/lib/vty.c
@@ -1685,6 +1685,7 @@
 vty_accept (struct thread *thread)
 {
   int vty_sock;
+  struct vty *vty;
   union sockunion su;
   int ret;
   unsigned int on;
@@ -1769,7 +1770,7 @@
   if (bufp)
     XFREE (MTYPE_TMP, bufp);
 
-  vty_create (vty_sock, &su);
+  vty = vty_create (vty_sock, &su);
 
   return 0;
 }