ci-status with remote repository specification with -r

When local repository's remotes are like:

* a-mine https://github.com/_username_/hub.git
* origin https://github.com/github/hub.git

Then run `ci-status` fetches always from 'a-mine' remote's build status. This
commit make it possible to choose remote repository's commit build status with
-r option like:

    hub ci-status -r origin __commit_sha__

You can also use -v option to retrieve build url

    hub ci-status -r origin __commit_sha__ -v