vold: restore 4.4 sdcard logic

Mount points in 4.4 are always fuse-wrapped to provide granular
permission. Unix file systems no longer need to be manually
fuse-wrapped by us.

Change-Id: I6885b0baeaae7c380ec32d410a70a4f53801157b
Merge "vold: restore 4.4 sdcard logic" into cm-11.0