fix sed errors when build on Mac

[ailisp]

This fix is from @oatmealraisin . On Mac OS X 10.13.4, go generate will give a list of errors:

sed: 1: "protobuf//consensus_pb2 ...": extra characters at the end of p command
sed: 1: "protobuf//setting_pb2/s ...": extra characters at the end of p command
sed: 1: "protobuf//client_receip ...": extra characters at the end of p command
sed: 1: "protobuf//client_peers_ ...": extra characters at the end of p command
sed: 1: "protobuf//network_pb2/n ...": extra characters at the end of p command
sed: 1: "protobuf//authorization ...": extra characters at the end of p command
sed: 1: "protobuf//client_transa ...": extra characters at the end of p command
sed: 1: "protobuf//genesis_pb2/g ...": extra characters at the end of p command
sed: 1: "protobuf//client_event_ ...": extra characters at the end of p command
sed: 1: "protobuf//identity_pb2/ ...": extra characters at the end of p command
sed: 1: "protobuf//client_batch_ ...": extra characters at the end of p command
sed: 1: "protobuf//processor_pb2 ...": extra characters at the end of p command
sed: 1: "protobuf//block_pb2/blo ...": extra characters at the end of p command
sed: 1: "protobuf//merkle_pb2/me ...": extra characters at the end of p command
sed: 1: "protobuf//transaction_r ...": extra characters at the end of p command
sed: 1: "protobuf//events_pb2/ev ...": extra characters at the end of p command
sed: 1: "protobuf//client_batch_ ...": extra characters at the end of p command
sed: 1: "protobuf//client_list_c ...": extra characters at the end of p command
sed: 1: "protobuf//client_state_ ...": extra characters at the end of p command
sed: 1: "protobuf//client_block_ ...": extra characters at the end of p command
sed: 1: "protobuf//transaction_p ...": extra characters at the end of p command
sed: 1: "protobuf//batch_pb2/bat ...": extra characters at the end of p command
sed: 1: "protobuf//client_status ...": extra characters at the end of p command
sed: 1: "protobuf//validator_pb2 ...": extra characters at the end of p command
sed: 1: "protobuf//state_context ...": extra characters at the end of p command

And this fix works on both Linux (gnu sed) and Mac (bsd sed)

[peterschwarz]

@wkatsak Is this still relevant after the merging of PR #43?

[wkatsak]

@peterschwarz This may still be relevant but definitely needs to be rebased against main and tested before merge.

[vaporos]

See discussion above - please rebase and re-open.