Specify Protobuf version 2 in paymentrequest.proto
Specify Protobuf version 2 in paymentrequest.proto

(cherry picked from commit c4084c208509c42f796ebaa3eaded5f1cd40c506)

reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin,reddcoin-project/reddcoin