security_StatefulPermissions: allow attestation db ownership

BUG=chrome-os-partner:46244
TEST=test_that security_StatefulPermissions

Change-Id: Ie3287b1a7a676dfa3810ff186b38507438392d4c
Reviewed-on: https://chromium-review.googlesource.com/315225
Commit-Ready: Darren Krahn <dkrahn@chromium.org>
Tested-by: Darren Krahn <dkrahn@chromium.org>
Reviewed-by: Jorge Lucangeli Obes <jorgelo@chromium.org>
(cherry picked from commit 68562714163261015f142b8df14364c772515dcd)
Reviewed-on: https://chromium-review.googlesource.com/318870
Reviewed-by: Darren Krahn <dkrahn@chromium.org>
Tested-by: Jorge Lucangeli Obes <jorgelo@chromium.org>
diff --git a/client/site_tests/security_StatefulPermissions/security_StatefulPermissions.py b/client/site_tests/security_StatefulPermissions/security_StatefulPermissions.py
index bd83dfa..a8b7f44 100644
--- a/client/site_tests/security_StatefulPermissions/security_StatefulPermissions.py
+++ b/client/site_tests/security_StatefulPermissions/security_StatefulPermissions.py
@@ -20,6 +20,7 @@
     # Note that chronos permissions in /home are covered in greater detail
     # by 'security_ProfilePermissions'.
     _masks_byuser = {"adm": [],
+                     "attestation": ["/unencrypted/preserve/attestation.epb"],
                      "avfs": [],
                      "bin": [],
                      "bluetooth": ["/encrypted/var/lib/bluetooth"],