Fix npm to use https rather than http
    
    Hit this error while building nlf-native recently:
    {
      "error": {
        "summary": "URI malformed",
        "detail": ""
      }
    }
    
    Some poking about led me to discover that:
    1) The npm.py tool replaces npm:// with http://, not https://
    2) Some versions of the npm tool don't handle 301 redirects properly,
       choosing to display the above error instead when using the default
       nodejs registry
    
    It would be good to go fix npm to handle the redirect properly, but it
    seems like it would also be good to assume secure http when contacting a
    registry, hence, this patch
    
    Signed-off-by: Neil Horman <nhorman@gmail.com>
    Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>