datacollect and shutdown hooks not called from batch mode

```
Using 'core -b' to start a scenario in batch mode, then 'core -c' to shutdown,
hooks for the datacollect and shutdown states are not invoked.

Two different code paths:
1. For 'core -c' a Session Message is sent with the delete flag.
2. For the stop button (GUI), first a datacollect event is sent, then node and
link delete messages, and cored decides when to enter the shutdown state.
```

Original issue reported on code.google.com by `ahrenh...@gmail.com` on 8 Mar 2013 at 3:48