chromeos_power: Fix power manager dbus paths They should be kPowerManagerServicePath instead of "/". BUG=chromium-os:20115 TEST=Make sure power supply readings in power manager still work. Change-Id: Ic1b1af1010c0ef3f5bcfa130c0751780608ac9c4 Signed-off-by: Simon Que <sque@chromium.org> Reviewed-on: http://gerrit.chromium.org/gerrit/8064 Reviewed-by: Satoru Takabayashi <satorux@chromium.org>