Call ref/unref, bugfixes
diff --git a/src/cpp/client/client_context.cc b/src/cpp/client/client_context.cc
index 3d884cf..2516232 100644
--- a/src/cpp/client/client_context.cc
+++ b/src/cpp/client/client_context.cc
@@ -74,7 +74,7 @@
 
 ClientContext::~ClientContext() {
   if (call_) {
-    grpc_call_destroy(call_);
+    grpc_call_unref(call_);
   }
   g_client_callbacks->Destructor(this);
 }