Fix dropdown for replace not not populating correctly

    - Add correct optionValuePath to RiakControl.ClusterItemSelectView
    - Change `replacement` to `content.replacement` because once I fixed the dropdown,
      it exposed another bug where the replacement field in the staged plan wasn't populating
Merge pull request #171 from basho/jgn-fix-replace-dropdown

Fix dropdown for replace not not populating correctly
Merge branch 'develop' into jgn-cluster-stats-2
Add node tags to graphs