Don't try to restore VM's in state ERROR.

We don't try to restore VM's that are in a failed BUILDING state, so
attempting to start ERROR VMs is more than a little weird. The one
exception to this rule are VMs that are in RESIZE_MIGRATING, since
recovery is already attempted. It's also a problem, because many ERROR
states aren't recoverable from (at the moment anyhow).

Closes-Bug: #1272623
Change-Id: I0599b83a82ad3ee67a92126d3b57df5b02e20539
Co-Authored-By: Robert Collins <rbtcollins@hp.com>
Merge "Don't try to restore VM's in state ERROR."