Fix addAuthToken api

A binder token is not written thus cannot be read

Change-Id: Id44acf3e7001f2b027041ef8c7c324e687ab0fcd
diff --git a/keystore/IKeystoreService.cpp b/keystore/IKeystoreService.cpp
index d3cec50..d58f5ec 100644
--- a/keystore/IKeystoreService.cpp
+++ b/keystore/IKeystoreService.cpp
@@ -1774,7 +1774,6 @@
         }
         case ADD_AUTH_TOKEN: {
             CHECK_INTERFACE(IKeystoreService, data, reply);
-            sp<IBinder> token = data.readStrongBinder();
             const uint8_t* token_bytes = NULL;
             size_t size = 0;
             readByteArray(data, &token_bytes, &size);