Fix for stop_deployment test

Task on deployment or provisioning should be in status 'running' for
checking stopping deployment. tick_interval parameter added into
fake_tasks decorator for test_stop_deployment. Without it in some
cases tasks became into status 'ready' before stop deployment is
started

Change-Id: I57bf618f9d80312903e859a670c34b051e1bd206
Closes-Bug: #1330895
Merge "Fix for stop_deployment test"