removed a reference to a google3 dir

src/ruby/bin/interop/README.md

@@ -1,11 +1,8 @@
 Interop test protos
 ===================
 
-These were generated by a patched version of beefcake and a patched version of
+These ruby classes were generated with protoc v3, using grpc's ruby compiler
-protoc.
+plugin.
 
-- set up and access of the patched versions is described in ../../README.md
+- As of 2015/01 protoc v3 is available in the
-
+[google-protobuf](https://github.com/google/protobuf) repo
-The actual test proto is found in Google3 at
-
-- third_party/stubby/testing/proto/test.proto