[OHAI-518] remove *.static.cloud-ips.com

Fixes issues with Pull Request #215
- fixes tests
- moves `require "resolve"` to top of file
I think you need to split this into two separate tests here. you could make it DRY with something like

```
[ Resolv::ResolvError, Resolv::ResolvTimeout ].each do |exception|
  it "should return ip address when reverse dns returns exception: #{exception}" do
    Resolv.stub(:getname).and_raise(exception)
    @plugin.run
    @plugin[:rackspace][:public_hostname].should == "1.2.3.4"
  end
end
```