init: Add setup_fs service for Userdata

* Used for formatting data after unlock,
  as the userdata partition is zeroed out after unlock,
  but a filesystem isn't created.

Change-Id: I17aba9ed9778431e48f9605d10a7fde8be9b7b86
Merge pull request #6 from CyanogenMod/cm-11.0

init: Add setup_fs service for Userdata