Fix enabled log_exchange issue
Fix enabled log_exchange issue

If log_exchange is enabled, it fails to load v2 app.

This patch fixes this issue by initializing debug middleware
after setup_app method as 'Debug' middleware expects global_conf
type as dict instead of 'pecan.conf' which doesn't have copy method.

Change-Id: I65742b261b7b1429b399a78d19cdaf85ef28b917
Closes-Bug: #1803037

openstack/blazar,ChameleonCloud/blazar,stackforge/blazar,stackforge/blazar,openstack/blazar,ChameleonCloud/blazar