vold: Do not cache CE keys in vold

CE keys were cached in vold to support untrusted reset
by a device admin, this is now supported by Locksettingservice
using synthetic password. This change requires a secret to be
provided to retrieve the CE key and re-wrap without the secret
when user removes the credential.

Test: Set credential, remove credential, swipe to none
and vice-versa.
Bug: 26948053
Merged-In: I4cb1c035a472477e70c1ff5bf0b2c3fcfad495e5
Change-Id: I4cb1c035a472477e70c1ff5bf0b2c3fcfad495e5
diff --git a/VoldNativeService.h b/VoldNativeService.h
index 0718263..18551f2 100644
--- a/VoldNativeService.h
+++ b/VoldNativeService.h
@@ -112,6 +112,8 @@
 
     binder::Status addUserKeyAuth(int32_t userId, int32_t userSerial, const std::string& token,
                                   const std::string& secret);
+    binder::Status clearUserKeyAuth(int32_t userId, int32_t userSerial, const std::string& token,
+                                    const std::string& secret);
     binder::Status fixateNewestUserKeyAuth(int32_t userId);
 
     binder::Status unlockUserKey(int32_t userId, int32_t userSerial, const std::string& token,