instance_get_all_by_filters now does 2 DB queries, but they can be consolidated into 1.

[Chris Behrens]

2nd DB query needs to go away. You can add this to the first one:

if instance_uuids:
    query_prefix = query_prefix.filter(models.Instance.uuid.in_(instance_uuids))

And then restore the old: instances = query_prefix.all() that should go right before the regexp filtering.