ctdb-common: Replace pcap_open_live() by lower level calls

ctdb-common: Replace pcap_open_live() by lower level calls

A subsequent commit will insert an additional call before
pcap_activate().

This sequence of calls is taken from the source for pcap_open_live(),
so there should be no change in behaviour.

Given the defaults set by pcap_create_common(), it would be possible
to omit the calls to pcap_set_promisc() and pcap_set_timeout().
However, those defaults don't seem to be well documented, so continue
to explicitly set everything that was set before.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=15451

Signed-off-by: Martin Schwenke <mschwenke@ddn.com>
Reviewed-by: Amitay Isaacs <amitay@gmail.com>