fixed a fd leak when trying to regain contact to a domain controller

in winbind

When a w2k3 DC is rebooted the 139/445 ports come up before the
udp/389 cldap port. During this brief period, winbind manages to
connect to 139/445 but not to udp 389. It then enters a tight loop
where it leaks one fd each time. In a couple of seconds it runs out of
file descriptors, and leaves winbind crippled after the DC does
finally come up
(This used to be commit 57187cafbc)

source3/winbindd/winbindd_cm.c

@@ -1320,6 +1320,7 @@ static bool find_new_dc(TALLOC_CTX *mem_ctx,
 	TALLOC_FREE(addrs);
 	num_addrs = 0;
 
+	close(*fd);
 	*fd = -1;
 
 	goto again;