(SIMP-1517) Reorganize builder options
(SIMP-1517) Reorganize builder options

This moves the SSH options above the `boot_command` and puts the
shutdown command at the end.  This is a somewhat more logical order
based on the order in which they are set or executed.

Change-Id: I0aa6b971f9f15cf1f6acded007c81c72457dcc16

cmentzer/simp-packer