Revert "Add NTFS support in vold"

Ignore-AOSP-First: Change already merged in AOSP, has same change ID, so
manually merging into master.
This reverts commit 564f6c64.

Reason for revert: Un-backporting.

Note: This is not a direct revert. We should keep the minor refactoring
in PublicVolume.cpp; no point making the code worse.

Test: Revert.
Change-Id: I68e31bd55158ea06af4f42f14723d3404d63f6d5