zenfone6: dont track Servicetracker

Change-Id: Ib1d8f7dd083f88f3f657bfcb201085c49925b1b5
diff --git a/system.prop b/system.prop
index b8a8abe..9fd2221 100644
--- a/system.prop
+++ b/system.prop
@@ -246,3 +246,4 @@
 ro.build.asus.sku=WW
 ro.vendor.qti.va_aosp.support=1
 persist.google.assistant.enable=1
+sys.vendor.qti.servicetracker.disable=true