Fix rpcbind init after r300941.

• getaddrinfo() sets res = NULL on failure and freeaddrinfo() always dereferences its argument, so we should only free the address list after a successful call.
• Address a second potential leak caused by getaddrinfo(AF_INET6) overwriting the address list returned by getaddrinfo(AF_INET).

X-MFC-With: r300941