return record should encode with latin

shoud encode return record with 'latin', eg：'220'.encode() will get '\xc3\x9c'
```
class A(DNSResponse):
    def __init__(self, query, record):
        super(A, self).__init__(query)
        self.type = b"\x00\x01"
        self.length = b"\x00\x04"
        self.data = self.get_ip(record).encode('latin')  <----
```