The OpenStack SDK performs a lot of processing on the JSON data
returned by nova, and on large server lists, this can dwarf the
actual time needed to receive and parse the JSON.
Nodepool uses very little of this information, so let's use the
keystoneauth session to get a simple JSON list.
The Server object that SDK normally returns is a hybrid object
that provides both attributes and dictionary keys. One method
that we call has some lingering references to accessors, so we
create a UserDict subclass to handle those. Nodepool-internal
references are updated from attributes to dictionary keys.
Change-Id: Iecc5976858e8d2ee6894a521f6a30f10ae9c6177
James E. Blair
066699f88a