Controller and API changes for backups.

-API controller for backups
-adding swift url to the config
-Fixing failing tests
-Renaming 'instance' param.
 Checking for NotFound models so that the returned error is friendly
-adding feature to list all backups from a specific instance
-Adding checks for creating/deleting/restoring backups when it is not completed
-Adding unit tests for backup controller
-adding check to see if file is in swift
-Adding skeleton code for delete backup in the task manager
-Fixed backups API to pass in the backup_id during create_backup.
-adding int tests for backup controller
-Adding backup list and delete int tests
-Adding list backups for instance test
-Adding quota for create backup

BP: https://blueprints.launchpad.net/reddwarf/+spec/consistent-snapshots

Change-Id: I35c2fefcce4b3009e76ba7232c52dabf502a3ac0