POC: Mounting Deltacloud API as a Rack middleware

Hi,

This is an updated PR with some fixes to make this POC work with the latest Deltacloud API.
In order to test it out, you need to have the latest DC installed (1.1.3-pre). You can download this gem from [here](http://omicron.mifo.skdeltacloud-core-1.1.3.gem). To install this type:

`gem install deltacloud-core-1.1.3.gem --local`

This PR contains updated Gemfile and Gemfile.lock to require this deltacloud-core.

Also I fixed issue with fog/rbovirt dependency as they are required already by deltacloud-core (so you don't need to have them in Gemfile).