Ensure /data/data isn't writable.

Change-Id: If569f3c23b939736d6604fe46ae671d2657a7e73
diff --git a/tests/tests/permission/src/android/permission/cts/FileSystemPermissionTest.java b/tests/tests/permission/src/android/permission/cts/FileSystemPermissionTest.java
index 61c458f..317ed83 100644
--- a/tests/tests/permission/src/android/permission/cts/FileSystemPermissionTest.java
+++ b/tests/tests/permission/src/android/permission/cts/FileSystemPermissionTest.java
@@ -200,6 +200,7 @@
                     "/data/btips/TI",
                     "/data/btips/TI/opp",
                     "/data/dalvik-cache",
+                    "/data/data",
                     "/data/data/.drm",
                     "/data/data/.drm/.wmdrm",
                     "/data/dontpanic",