Revert "vold [3]: support more than 1 UMS share"

This reverts commit 10f16bdfad179790671d1b0df49327f6e9973112.

Conflicts:
	VolumeManager.cpp
	VolumeManager.h
Squash UMS Commits [3/3]

Change-Id: I6ef62640e9c6323f6cf940d9f63bd372e9e29b9d
Credits: CyanogenMod