Remove usage dependancies from everywhere else.

Can now disable usage module by disabled it in karaage/conf/defaults.py,
and everything should continue to work.

Change-Id: Id236252aa877d9ce461fe5b089f7710572c39171
Change UserApplication logs to Application logs.

Change-Id: Ife1a9ce3044a5234ba140a17e2d7723277e6fb1b