ctdb-tcp: Only attempt to automatically bind to local IPs

ctdb-tcp: Only attempt to automatically bind to local IPs

Automatic node address selection in the TCP transport does not work if
net.ipv4.ip_nonlocal_bind=1 because all nodes will be able to bind()
to the first address in the nodes list.

Before getting to the bind() step, add a check to see if an address is
local (i.e. on an interface).  If not, it is not considered.

This is defensively coded so that this step is skipped if local
addresses can not be retrieved.

Signed-off-by: Martin Schwenke <mschwenke@ddn.com>
Reviewed-by: John Mulligan <jmulligan@redhat.com>
Reviewed-by: Anoop C S <anoopcs@samba.org>