Remove update_engine from dbus group.

Bug: 31602715
Test: update_engine_client --status
Change-Id: I32f867b96bd7e16c9acfaa6afba8647b6dd59e6f
diff --git a/update_engine.rc b/update_engine.rc
index 88cf120..b6a706a 100644
--- a/update_engine.rc
+++ b/update_engine.rc
@@ -1,5 +1,5 @@
 service update_engine /system/bin/update_engine --logtostderr --foreground
     class late_start
     user root
-    group root system wakelock dbus inet cache
+    group root system wakelock inet cache
     writepid /dev/cpuset/system-background/tasks