Add basic InstanceFault model

This adds a basic InstanceFault model, list, and tests.

Related to blueprint unified-objet-model

Change-Id: I9226bc1f6e21d298b6d5d8694d336d38e471846d
Add Instance.fault

This makes Instance load fault as an optional attribute, if
requested. I didn't implement save for this, as I'm not sure
we will (want to) support setting instance faults via that
interface.

Related to unified-object-model
Fixes bug 1192004

Change-Id: I581e1f49c4c593ece97cf32dc7cea3f7a7cbd953
Make NovaObject support the 'in' operator

This is needed for dict emulation.

Related to unified-object-model

Change-Id: I6e024dc284a353181d3ffc84329f234e16b79118
Merge "Add basic InstanceFault model"
Merge "Add Instance.fault"
Merge "Make NovaObject support the 'in' operator"
Merge remote-tracking branch 'm_src_repo/citrix-fixes' into build-temp