Config graceful_shutdown_timeout option for services

To avoid hanging services during gracefull shutdown option
graceful_shutdown_timeout should be configured.

Closes-Bug: #1446583

Change-Id: I2b7f0df831d65c55ae8cae241478f49c9641d99f
diff --git a/lib/nova b/lib/nova
index 6c41403..cce598d 100644
--- a/lib/nova
+++ b/lib/nova
@@ -649,6 +649,7 @@
         iniset $NOVA_CONF serial_console serialproxy_host "$NOVA_SERVICE_LISTEN_ADDRESS"
         iniset $NOVA_CONF serial_console enabled True
     fi
+    iniset $NOVA_CONF DEFAULT graceful_shutdown_timeout "$SERVICE_GRACEFUL_SHUTDOWN_TIMEOUT"
 }
 
 function init_nova_cells {