Use wraps decorator
Use wraps decorator

Use wraps decorator from functools library.
This calls the update_wrapper method from functools
which sets these built-in values to those of the
wrapped function.

Change-Id: I3df3d4e8dbbbbcf384436441349c05386f2b0743

masayukig/tempest,cisco-openstack/tempest,openstack/tempest,masayukig/tempest,cisco-openstack/tempest,openstack/tempest