socketlib: properly fix the IPv6 to IPv4 fallback code.

With the current code, we do have the following on a system where IPv6
is completely disabled:

socket(PF_INET6, SOCK_STREAM, IPPROTO_IP) = -1 EAFNOSUPPORT (Address
family not supported by protocol)
socket(PF_INET, SOCK_STREAM, IPPROTO_IP) = 3
setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0
bind(3, {sa_family=AF_INET6, sin6_port=htons(5002), inet_pton(AF_INET6,
"::", &sin6_addr), sin6_flowinfo=0, sin6_scope_id=0}, 28) = -1
EAFNOSUPPORT (Address family not supported by protocol)

The correct fix is to make a new call to getAddr() to ensure that the
entire struct addrinfo will be correctly filled out again with AF_INET
this time. This patch fixes this.