power: Don't emit PowerStateChanged and SuspendStateChanged.

These D-Bus signals are being removed in favor of
simpler SuspendImminent and SuspendDone signals.

BUG=chromium:359619
TEST=updated tests

Change-Id: Ie49e8377593fbd672e81ff846c889a08d734ce8d
Reviewed-on: https://chromium-review.googlesource.com/196274
Commit-Queue: Daniel Erat <derat@chromium.org>
Tested-by: Daniel Erat <derat@chromium.org>
Reviewed-by: Sameer Nanda <snanda@chromium.org>
4 files changed