Fixed battery percentage icon not displaying properly

Disable battery firmware version check at upstart script.
Please enable it if and only if the following glimmer firmare is landed.

This upstart script depends on these glimmer firmare.
TARGET_FWID="Google_Glimmer.5216.198.35"
TARGET_ECID="glimmer_v1.6.185-7c54721"

BUG=chromium:497809
BRANCH=glimmer
TEST=Begin
1. Normal Power on and check battery icon
2. EC-Power cycle (Power Button + Refesh Key); check battery icon
3. login and wait for 5 minutes; check battery icon
End

Reviewed-on: https://chromium-review.googlesource.com/276801
Reviewed-by: Bernie Thompson <bhthompson@chromium.org>
Signed-off-by: Bernie Thompson <bhthompson@chromium.org>

Signed-off-by: Sheng-Liang Song <ssl@chromium.org>

Change-Id: I226ad11239c4f4b9d85afb834e16f907d1c63d81
Reviewed-on: https://chromium-review.googlesource.com/277543
Reviewed-by: Sheng-liang Song <ssl@chromium.org>
Commit-Queue: Sheng-liang Song <ssl@chromium.org>
Tested-by: Sheng-liang Song <ssl@chromium.org>

scripts/chromeos-battery-update.conf

diff --git a/scripts/chromeos-battery-update.conf b/scripts/chromeos-battery-update.conf
index bb01bdd..dd818c9 100644
--- a/scripts/chromeos-battery-update.conf
+++ b/scripts/chromeos-battery-update.conf
@@ -5,6 +5,6 @@
 description     "Battery firmware and config updater for Chromebooks"
 author          "chromium-os-dev@chromium.org"
 
-# This job has no main script so that it only runs once at boot.
-start on started system-services
+# This job will not run automatically as it lacks a "start on" statement.
+task
 exec /opt/google/battery/scripts/chromeos-battery-update.sh