Root of /data belongs to init (re-landing)

Give /data itself a different label to its contents, to ensure that
only init creates files and directories there.

This change originally landed as aosp/1106014 and was reverted in
aosp/1116238 to fix b/140402208. aosp/1116298 fixes the underlying
problem, and with that we can re-land this change.

Bug: 139190159
Bug: 140402208
Test: aosp boots, logs look good
Change-Id: I1a366c577a0fff307ca366a6844231bcf8afe3bf
diff --git a/private/traced.te b/private/traced.te
index 2d7d07f..42c6704 100644
--- a/private/traced.te
+++ b/private/traced.te
@@ -62,6 +62,7 @@
 neverallow traced {
   data_file_type
   -system_data_file
+  -system_data_root_file
   # TODO(b/72998741) Remove vendor_data_file exemption. Further restricted in a
   # subsequent neverallow. Currently only getattr and search are allowed.
   -vendor_data_file