If an admin has set the DISALLOW_FACTORY_RESET user restriction, OEM
unlock is also restricted. If this is the case, it should be explained
to the user that the admin is preventing the OEM unlock.
DISALLOW_OEM_UNLOCK is deprecated and now managed by OemLockManager.
This restriction is also one set by the carrier, not an admin.
Test: RunSettingsRoboTests
Test: CTS verifier test from the bug
Bug: 65124732
Change-Id: I8bde87a522742a7cbda006eee17c2a19797b1835
Previously, the PersistentDataBlockService but that is only one possible
implementation of the OEM lock. The new service abstracts the
implementation so is the API that should be used.
Test: Manual
Bug: 34766843
Change-Id: I5f9cb94996f84c4c082d152f05cd8aef566edc66
