Getting initdevice working on PostGRE

This localizes the logic out of SyncModel and into Device. Uses the "imported" codepath to accomplish goals--save without signing, and without mucking with counters (which is the codepath that breaks in postgre)

This code path is only hit during installation, so should be low impact.  I believe the code is a bit cleaner (with documentation as to why we're using the "imported" codepath).

@gimick can you test this out?