Bug 1064616: If a 'try' repo do not show 'unclassified failures in last 24 hours'

Looking this over, an easier way occurred to me.  We should add the group name to each object in the ``watchedRepos`` list.  That way you can just access that directly from the HTML, without the need for this method.  ``watchedRepos`` actually gets populated from the full list of repos we pull from the server in ``addRepoAsUnwatched``.  In this function we have access to the repo group and could just add it as a field to the object like this:
    var addRepoAsUnwatched = function(repo) {
        repos[repo.name] = {
            treeStatus: null,
            unclassifiedFailureCount: 0,
            unclassifiedFailureCountExcluded: 0,
            groupName: repo.repository_group.name
        };
    };

then in the directive, you can get that value directly in ``scope.repoData``