vold: allow non-vfat devices to be used as ASEC

CM supports alternative file systems (which some devices specify
in the fstab as 'auto').

Change-Id: I7e78fe87a7efc49d6749d5892107085d55156cce
vold: support more than 1 UMS share

Used for devices with both mountable internal and external sdcards.

This is a forward-port and clean up of the 10.2 code (which contains
a lot of deadcode.)

Original authors:

    Alex Zepeda <alex@inferiorhumanorgans.com>
    Genokolar <genokolar@gmail.com>
    Josh Stone <cuviper@gmail.com>
    mik_os <kiril.mik.os@gmail.com>
    Oran Avraham <oranav@gmail.com>
    Pawit Pornkitprasan <p.pawit@gmail.com>
    Tony Layher <layhertony@gmail.com>

Change-Id: I926ce244255414697373d26d252a9da89aea7226
vold: Support external non-emulated storage

It tries to acess EMULATED_STORAGE_SOURCE which is not
defined if the device doesnt have an emulated storage

mkdirs() also needs to be valid for EXTERNAL_STORAGE

See also https://github.com/CyanogenMod/android_system_vold/commit/5ced6afb769f09ada6e3d1787a36c6f9f8469ed6

Change-Id: I6463979a06eab301acd59e815713abc3f550853f

Conflicts:
	VolumeManager.cpp