s/CreateChannel/CreateChannelDeprecated

For the 2-argument version of CreateChannel.

This is a temporary step until #711 is ready to roll out.
diff --git a/test/cpp/end2end/async_end2end_test.cc b/test/cpp/end2end/async_end2end_test.cc
index 248e054..c36ff42 100644
--- a/test/cpp/end2end/async_end2end_test.cc
+++ b/test/cpp/end2end/async_end2end_test.cc
@@ -105,7 +105,7 @@
 
   void ResetStub() {
     std::shared_ptr<ChannelInterface> channel =
-        CreateChannel(server_address_.str(), ChannelArguments());
+        CreateChannelDeprecated(server_address_.str(), ChannelArguments());
     stub_.reset(grpc::cpp::test::util::TestService::NewStub(channel));
   }