Add input & output params to begin operations.

This is in preparation for handling IV/nonce values via params rather
than prepended to ciphertext.

Change-Id: I657a029eaf66c2218c3f7cc149e86e9d01c41be0
diff --git a/google_keymaster.cpp b/google_keymaster.cpp
index af0ece3..056f643 100644
--- a/google_keymaster.cpp
+++ b/google_keymaster.cpp
@@ -234,7 +234,8 @@
     if (operation.get() == NULL)
         return;
 
-    response->error = operation->Begin();
+    response->output_params.Clear();
+    response->error = operation->Begin(request.additional_params, &response->output_params);
     if (response->error != KM_ERROR_OK)
         return;