raise form error when bad iarc submission id, allow subm- prefix (bug 939230)

![screen shot 2013-11-15 at 7 09 57 pm](https://f.cloud.github.com/assets/674727/1555616/a502b624-4e6d-11e3-9a32-22804f78f613.png)
![screen shot 2013-11-15 at 7 09 49 pm](https://f.cloud.github.com/assets/674727/1555617/a5e31a34-4e6d-11e3-9b6d-a67d166024f2.png)


![](http://s3-ec.buzzfed.com/static/2013-11/enhanced/webdr05/14/14/anigif_enhanced-buzz-533-1384458783-62.gif)