Don't print out debug messages at level 0 if we can't

Don't print out debug messages at level 0 if we can't
bind to a socket if we've already bound to one (this
prevents :
bind failed on port 445 socket_addr = 0.0.0.0.
Error = Address already in use
bind failed on port 139 socket_addr = 0.0.0.0.
Error = Address already in use
messages when trying to bind to an IPv4 address
when we've already bound to the IPv6 equivalent.
Jeremy.
(This used to be commit 3936de735a7bb548df8ce7f06f2cc8f7ffdf56cd)