Use explicit http error code for api v2

* not exist should be 404
* conflict should be 409
* not authorized should be 401

Change-Id: Ied88290c42e5679761e6d50073c7965c5644f84e
Closes-Bug: #1271525
Updated from global requirements

Change-Id: I203139f530cbaf256fc7f90de9f06c3b3f480096
Merge "Updated from global requirements"
Merge "Use explicit http error code for api v2"