Remove warn log for over quota

Over quota exception is already raised at API layer
and no need to print a warning log.

Change-Id: If44d5f2dd0e11d15d57cf6ab247f5e9e7fe75a9c
Add i18n log markers in disk api

    Improve LOG i18n log markers in nova/virt/disk/api.py.

Change-Id: I76b5a2acc15bd4230ea6e243770ac0590c56235d
Merge "Remove warn log for over quota"
Merge "Add i18n log markers in disk api"