Create a swap partition if needed for new servers

Add a script to  handle cloud servers with no swap. This can be
used before install_puppet when developers run it by hand, and
is called directly by launch_node. If the host has
no swap, create a swap partition from the ephemeral disk and use
the remainder on /opt.

Change-Id: Iac8bfe4924d8607ddbddc45312a51fe52eb4cdbc
Merge "Create a swap partition if needed for new servers"