Use ssl.wrap_socket instead of socket.ssl

Simple fix to make xmmppy work on ubuntu 14.10 with libpython2.7-stdlib version 2.7.8-10ubuntu1 as it appears that socket.ssl is broken/deprecated with this version.

This code should work with python >= 2.6
Can you please fix this ident issue ? to something like:

```python
    tcpsock._sslObj    = ssl.wrap_socket(tcpsock._sock, None, None)
    tcpsock._sslIssuer = tcpsock._sslObj.getpeercert().get('issuer')
    tcpsock._sslServer = tcpsock._sslObj.getpeercert().get('server')
```