Merge pull request #8282 from dgquintas/udp_sp

added missing line to UDP server

src/core/lib/iomgr/udp_server.c

@@ -199,6 +199,7 @@ void grpc_udp_server_destroy(grpc_exec_ctx *exec_ctx, grpc_udp_server *s,
   /* shutdown all fd's */
   if (s->active_ports) {
     for (i = 0; i < s->nports; i++) {
+      server_port *sp = &s->ports[i];
       /* Call the orphan_cb to signal that the FD is about to be closed and
        * should no longer be used. */
       GPR_ASSERT(sp->orphan_cb);