Likely fix for #39.

I think that the upgrade from jClouds 1.4.2 to 1.5.1 in the previous
commit (9d6e47b7) made a change in how `.createSecurityGroupInRegion`
works (see security.clj).
Working on eu-west-1 rather than us-east-1

The AMI Name is
"ubuntu/images/ubuntu-precise-12.04-amd64-server-20121218"