Fix arcs-live deploy: Incorrect npm version (#4155)
Fix arcs-live deploy: Incorrect npm version (#4155)

* added cmd to install correct npm version

* using node from .nvmrc; using latest npm

* Installing npm specified by package.json
- should specifically work on travis, because it has `jq` installed

PolymerLabs/arcs,PolymerLabs/arcs,PolymerLabs/arcs,PolymerLabs/arcs,PolymerLabs/arcs,PolymerLabs/arcs,PolymerLabs/arcs,PolymerLabs/arcs