Fix grafana build steps
Fix grafana build steps

All Grafana dependencies are vendored in its repository so it's not
needed to do `go get`.
To install Grafana we don't need to run `godep restore`, we simply need
to run `go run` with godep (it will use vendored dependencies instead
of the system wide).

Change-Id: Id08588331c6c430d53f9827c41f31d30185f8ca8

openstack/monasca-api,stackforge/monasca-api,stackforge/monasca-api,openstack/monasca-api,stackforge/monasca-api,sapcc/monasca-api,openstack/monasca-api,sapcc/monasca-api,stackforge/monasca-api,sapcc/monasca-api