Remove obsolete migration module
Run single check command in a task
Fix a wrong usage of the in statement
Prevent division by zero inside of reporter
Repair image-related task in snapshot migration flow

Pass user_id from server resources migration factory, use
user_id to compose rebind key for task creating corresponding user
in dst and rebind EnsureSingleImage task to output of that task.
Add tenant name to restrict when migrating image
Use linear flow for running checks

Instead of unordered flow, which behaves unpredictably, use linear
flow pattern for running check tasks after server boot.
Checks should be executed after assignment of floating ips

Move check flow after the floating ips assignment flow in main
server migration flow.
Adds tenant migrate and tenant migrated events emission
Correct syntax and logic of execution

The patch fixes the problem which prevents to emit the "tenant migrated"
event in case of errors.
Set unix fileformat for test_user
Introduce Context