Update listener.c
Update listener.c

fix for broken fallback option. 
memory allocated to listener->fallback_address is getting freed in resolve_server_address() of connection.c. In order to reuse listener->fallback_address, we copy it into new_addr and preserver  listener->fallback_address for subsequent fallback calls.
balyanrobin/sniproxy,balyanrobin/sniproxy,balyanrobin/sniproxy,balyanrobin/sniproxy