convert to proto3

[rainbow-ce]

Using protobuf 3.19.2

wget https://github.com/protocolbuffers/protobuf/releases/download/v3.19.2/protobuf-all-3.19.2.tar.gz
tar -xvf protobuf-all-3.19.2.tar.gz
cd protobuf-3.19.2/
./configure
make
make check
make install
ldconfig

Updated:

• In ltfsdm.proto
  • Remove all 'required', not valid in proto3
  • update version from proto2 to proto3
• In generated ltfsdm.pb.h
  • Remove final definition in class Command
• In LTFSDmComm.cc
  • MessageSize = this->ByteSize(); => MessageSize = this->ByteSizeLong();
• In Trace.h
  • stream.str().size() => (unsigned) stream.str().size()