apmanager: rename Device.InUsed to Device.InUse

This is a grammar nit, but it seems wise to deal with it before there
are too many clients depending on it.

BUG=none
TEST=FEATURES=test emerge-gizmo apmanager

Change-Id: I94ff5635c2ab878feed5ef91e418cdf1b19cc290
Reviewed-on: https://chromium-review.googlesource.com/296790
Commit-Ready: Garret Kelly <gdk@chromium.org>
Tested-by: Garret Kelly <gdk@chromium.org>
Reviewed-by: Zeping Qiu <zqiu@chromium.org>
5 files changed