Add username and IP to make nodescp usage simpler.

I think this makes `nodescp` script a bit easier to use by implicitly specifying the user and IP address.

This changes `nodescp` from:
```
./nodescp ${ENVIRONMENT} ${HOST} cookbooks/bcpc/files/default/bins/chef-client.deb ubuntu@${HOST}:/tmp/
```

to

```
./nodescp ${ENVIRONMENT} ${HOST} cookbooks/bcpc/files/default/bins/chef-client.deb /tmp/
```

@mihalis68, what do you think?  (If you are okay with it, feel free to merge.)