DO NOT MERGE Revert "Remove permission android.permission.WRITE_MEDIA_STORAGE"

We need this to allow MTP to access secondary external storage devices

This reverts commit 35a2ea2f.

Conflicts:

	data/etc/platform.xml

Change-Id: I0b139a0f3b369c1080831a5b3a48f5d9a330b1bb
Signed-off-by: Mike Lockwood <lockwood@android.com>