Add logging to image_members and image_tags

Adding exceptions logging in image_members and image_tags modules in
REST API.

Change-Id: I36d7425c033403dab030bf79c5249a90e0865e7e
Closes-Bug: 1349845
Related to bp refactoring-glance-logging
DocImpact
Merge "Add logging to image_members and image_tags"