DO NOT MERGE ANYWHERE: UsageStats: Use new settings key idle_duration2 for app idle

Ignores the old, re-appropriated key "idle_duration" which is now
set to a high value in order to force disable app idle on devices
with bug b/26355386

Bug:26355386
Change-Id: Iff9de843ad6e547d29c1583687fc7f7ce7e15090
(cherry picked from commit 1559fed4c47a4bd219e61f7d34e50d46b8929f8a)
3 files changed