Fix valgrind uninitialised value in external-RC

Change-Id: I75ca612ced307e9c5bc39028c04f4d2656599937

test/ratectrl_rtc_test.cc

diff --git a/test/ratectrl_rtc_test.cc b/test/ratectrl_rtc_test.cc
index dc204e94..4760d39 100644
--- a/test/ratectrl_rtc_test.cc
+++ b/test/ratectrl_rtc_test.cc
@@ -41,6 +41,8 @@
         frame_drop_thresh_(0) {
     memset(&svc_params_, 0, sizeof(svc_params_));
     memset(&layer_id_, 0, sizeof(layer_id_));
+    memset(&frame_params_, 0, sizeof(frame_params_));
+    frame_params_.frame_type = aom::kKeyFrame;
   }
 
   ~RcInterfaceTest() override = default;