Catch IOError raised by getaddrinfo()
Catch IOError raised by getaddrinfo()

getaddrinfo sometimes raises random IOError exceptions when
a name cannot be resolved (Python or stdlib bug?). Catch it like
the 'socket.gaierror' exceptions.

This fixes the TestDumbBlockingResolver test for me.

Jajcus/pyxmpp2,Jajcus/pyxmpp2