Fix typos in engine.service.py
Fix typos in engine.service.py

Fix small typos in comments

Change-Id: I4ef0639adc2f808d386c0be1354feb28be616ebb

openstack/senlin,stackforge/senlin,stackforge/senlin,openstack/senlin,openstack/senlin,tengqm/senlin-container,tengqm/senlin-container