Show fingerprint text in backup screen lock

When setting up fingerprint's backup screen lock, show a different
header text that says
"To use fingerprint, set {PIN/pattern/password}" instead of
"Choose your {PIN/pattern/password}".

Test: Manual. Existing tests pass
Bug: 62187833
Change-Id: If1084e64b99291a0eda63c174793b5a091ab4bae