clean up Freeing Interfaces logging
privsep-linux.c: use c99 variable declaration
call privsep_init earlier so we don't waste resources

Calling privsep_init too late will cause the privsep process to keep a copy
if the first iface list indefinitely.  It will also keep the raw socket
open needlessly.  This is wasteful.  Privsep before those things happen to
keep down the resource usage.