Optimize the instance fetched by floating_ips API
Optimize the instance fetched by floating_ips API

The floating_ips API fetches an instance without flavor information
and then passes it to the Network API, which eventually calls
_get_instrance_nw_info() which requires access to the flavor. This
triggers a lazy load in 100% of the situations, which is really not
necessary and wasteful.

This patch adds flavor to the list of pre-queried attributes on the
instances fetched by this API to help reduce that waste.

Change-Id: I15eae4e8c03739a34cef9c90989ad0615a96a963
Partial-Bug: #1540526

dims/nova,Juniper/nova,mikalstill/nova,BeyondTheClouds/nova,rahulunair/nova,zhimin711/nova,klmitch/nova,BeyondTheClouds/nova,jianghuaw/nova,Juniper/nova,cyx1231st/nova,mikalstill/nova,sebrandon1/nova,cloudbase/nova,CEG-FYP-OpenStack/scheduler,hanlind/nova,mahak/nova,cernops/nova,openstack/nova,dims/nova,hanlind/nova,gooddata/openstack-nova,mikalstill/nova,vmturbo/nova,vmturbo/nova,NeCTAR-RC/nova,rajalokan/nova,rajalokan/nova,bigswitch/nova,hanlind/nova,klmitch/nova,gooddata/openstack-nova,vmturbo/nova,gooddata/openstack-nova,sebrandon1/nova,rajalokan/nova,gooddata/openstack-nova,alaski/nova,cyx1231st/nova,jianghuaw/nova,Juniper/nova,phenoxim/nova,klmitch/nova,vmturbo/nova,cernops/nova,mahak/nova,phenoxim/nova,Juniper/nova,rahulunair/nova,NeCTAR-RC/nova,alaski/nova,klmitch/nova,openstack/nova,openstack/nova,cloudbase/nova,bigswitch/nova,sebrandon1/nova,cernops/nova,BeyondTheClouds/nova,zhimin711/nova,cloudbase/nova,jianghuaw/nova,mahak/nova,jianghuaw/nova,rahulunair/nova,rajalokan/nova,CEG-FYP-OpenStack/scheduler