Revert "Zygote: Restrict slave mountspace so Dalvik apps can mount system-wide volumes"

This reverts commit e28d5aab2c0ace33cc907259ea8663f5a53d1548.
If dalvik wants ASCII casing, it needs to ask for it.

http://elliotth.blogspot.com/2012/01/beware-convenience-methods.html

Bug: https://code.google.com/p/android/issues/detail?id=58359
Change-Id: I1601cda215ebc5995117323e40a684ad352fe733