From Gisle Vanem and me: fix some typoes of mine in the conversion to

From Gisle Vanem and me: fix some typoes of mine in the conversion to
the new pcap_create/pcap_activate model, use pcap->opt.source rather
than pcap->md.device in the activate routine (pcap->md.device isn't
set), don't free the pcap_t if the activate routine fails, fix the
error return code paths not to set handle_to_device, fix references to
pcap_close_dos() to refer to pcap_cleanup_dos() as we renamed the
routine.