selinux: Downgrade CMFM's domain

the filemanager doesn't need to be in platform_app. Put it in untrusted_app,
especially since it's a possible su client

Change-Id: I164853f2c8721d86b5b90677cb33032a3b491ff5
sepolicy: allow recovery read access to /data/media/ files and dirs

Change-Id: I41173d72e86f9cf4d79f7c46166eeb71dc19d2f4