Scripts on free that exceed the memory usage limit don't correctly indicate why they are killed

Instead, implies the script's exceeded the time limit.

```
Started run: 2014-09-15 09:28:51+00:00
tool/actually-run: line 11: 12743 Killed                  timeout --kill-after=1m 1h ./code/scraper
Run killed by ScraperWiki, taking more than 1 hour, and wouldn't exit upon request
Finished run: 2014-09-15 09:31:03+00:00 Exit code: 137
```
