Fix private volume DE data path for mounting data mirror

Also, fix the correct CE DE dir permission

Bug: 149027213
Bug: 133435829
Test: Due to bug b/148856669, after reverting ag/10156695
and aosp/1218838, can see virtual disk is mounted correctly
in adb shell mount, and test app works and mounted
correctly after pm move-package.

Change-Id: I18437187db14ae9b383fa3b8b4577273a3afb7a8