transport.go: minor typo fix (#2225)
transport.go: minor typo fix (#2225)


stanley-cheung/grpc-go,grpc/grpc-go,dfawley/grpc-go,dfawley/grpc-go,stanley-cheung/grpc-go,grpc/grpc-go,menghanl/grpc-go,menghanl/grpc-go,improbable-io/grpc-go,improbable-io/grpc-go,thinkerou/grpc-go,thinkerou/grpc-go