nfs-utils: pass native rpcsvc-proto to configureFlag
nfs-utils: pass native rpcsvc-proto to configureFlag

It was passing in the targetPlatform's rpcgen binary which exec format errors of
course

Co-authored-by: Matthew Bauer <36b958e71a3497df54c138eca2250535100c5292@gmail.com>

NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs