* fixed go vet issues on aws provider in master
* added support for dns, dns options and dns search for docker container.
On docker container resource you can specify dns_opts nad dns_search
which maps directly to docker --dns_opt and --dns_search parameters.
Allowing users to setup the embedded dns settings for their containers.
* fixed the asserts for the new features in tests.
fixed tests around DNS, DNS_OPTS and DNS_SEARCH
Daniel Portella