A single escape character is accepted by Name::parse, and doesn't round-trip

[saethlin]

Another finding from fuzzing.

use trust_dns_proto::rr::Name;
use trust_dns_proto::serialize::binary::{BinDecodable, BinEncodable};
fn main() {
    let name = Name::parse("\\", None).unwrap();
    println!("{:?}", name);
    let bytes = name.to_bytes().unwrap();
    println!("{:?}", bytes);
    let name = Name::from_bytes(&bytes).unwrap();
    println!("{:?}", name);
}

Outputs

"\\" None Name("")
Name("")
[0]
Name(".")

Name("") seems definitely wrong to me. Is Name::parse supposed to reject this string?