Added UM.DISALLOW_OEM_UNLOCK, Removed Global.OEM_UNLOCK_DISALLOWED.

Currently we used global setting to restrict user from enabling oem
unlock. As global settings can be chagned using adb, using user
restrictions instead.

Bug: 29893399
Change-Id: Ic83112a4838b8279bf50408a29ae205e0b8639ee
9 files changed