Don't back up / restore "we're in night mode"

Bug 27880039

Change-Id: Ida59c9e602b939038e4bb3f55a6bf96db8897348
diff --git a/core/java/android/provider/Settings.java b/core/java/android/provider/Settings.java
index f7e0e03..a78f468 100755
--- a/core/java/android/provider/Settings.java
+++ b/core/java/android/provider/Settings.java
@@ -6089,7 +6089,6 @@
             MOUNT_UMS_AUTOSTART,
             MOUNT_UMS_PROMPT,
             MOUNT_UMS_NOTIFY_ENABLED,
-            UI_NIGHT_MODE,
             SLEEP_TIMEOUT,
             DOUBLE_TAP_TO_WAKE,
             WAKE_GESTURE_ENABLED,