Alternative to 'glide up' when modifying 'glide.yaml'

In https://github.com/deis/workflow-cli/pull/128 we added logic around modifying a local `glide.yaml` with particular pkg/version values sent from the upstream `controller-sdk-go` PR job before building.

However, as noted in https://github.com/deis/workflow-cli/pull/128#discussion_r71023996, this may update other dependencies when we strictly only want the sdk dependency updated. Therefore, this ticket represents researching a better way to bring in a particular PR change in `controller-sdk-go`...