provisioners/docker: Check for whether the container is running is not working properly

Looks like I missed out [this Docker PR](https://github.com/dotcloud/docker/pull/2140) that introduced a change to what gets written on the `cidfile` and as a result [the check](https://github.com/mitchellh/vagrant/blob/4f17a70c4e1a412b3def65d0132d3e8a85c395f1/plugins/provisioners/docker/docker_client.rb#L55) for whether the container is running does not work (at least on 0.7.0) :(
 
With that change, the full container ID is written out to the `cidfile` instead of the short version that gets printed out by default with `docker ps -a -q`. The fix is to add a `-notruc` argument to `docker ps` but I'm not sure what versions exactly have that behavior.

I'll try to dig into this later on tonight