Use the new OemLockService to get OEM lock state.

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
5 files changed