IF LOCALHOST IS BOTH IPV4/IPV6 ENABLED.

The original patch removed default value of the bind-address option.
So, the default value became NULL. By coincedence NULL resolves
to 0.0.0.0 and ::, and since the server chooses first IPv4-address, 
0.0.0.0 is choosen. So, there was no change in the behaviour.

This patch restores default value of the bind-address option to "0.0.0.0".