Log at debug level when things are OK

StorageManagerService: android.os.ServiceSpecificException is expected if the user has not unlocked the device.

Bug: 151077642
Change-Id: I027250bcae132d9be9c16690478adb41467bfec4
Test: No

services/core/java/com/android/server/StorageManagerService.java

@@ -3213,6 +3213,9 @@ class StorageManagerService extends IStorageManager.Stub
             try {
                 mVold.unlockUserKey(userId, serialNumber, encodeBytes(token),
                         encodeBytes(secret));
+            } catch (ServiceSpecificException sse) {
+                Slog.d(TAG, "Expected if the user has not unlocked the device.", sse);
+                return;
             } catch (Exception e) {
                 Slog.wtf(TAG, e);
                 return;