Change Details

For functional tests, we need compiled protobuf.

1. Compile protobuf for python using `protobuf_generate_python` in CMake. 2. Add generated python modules to `sys.path`. 3. Add a 404 fallback for the HTTP server.

For functional tests,1. Compile protobuf for python using `protobuf_generate_python` in CMake. 2. Add generated python modules to `sys.path`. 3. we need compiled protobuf.Add a 404 fallback for the HTTP server.