totem: Inform RRP about membership changes

Services are informed about membership changes, but if same information
is needed inside totemrrp or totemnet, it's impossible to gather this
information.

Patch makes this possible for now only for RRP with empty callbacks.

Signed-off-by: Jan Friesse <jfriesse@redhat.com>
Reviewed-by: Christine Caulfield <ccaulfie@redhat.com>
totemnet: Add totemnet_member_set_active

totemnet_member_set_active together with transport specific
member_set_active makes possible for totemnet (and more interestingly
transport) to be informed about membership changes.

Signed-off-by: Jan Friesse <jfriesse@redhat.com>
Reviewed-by: Christine Caulfield <ccaulfie@redhat.com>
totemrrp: Implement *_membership_changed

All *_membership_changed calls totemnet_member_set_active passing 1 as
active parameter for joined nodes and 0 for left nodes.

Signed-off-by: Jan Friesse <jfriesse@redhat.com>
Reviewed-by: Christine Caulfield <ccaulfie@redhat.com>
totemudpu: Implement member_set_active

Member active is used for sending "multicast" messages only to members
of ring. This reduces network load if some nodes are intentionally down.
Only regular multicast message load is reduced (messages sent by
totemudpu_mcast_noflush_send), because special messages (like hold
cancel, join message, ...) still have to be send to all members to
ensure correct behavior.

Signed-off-by: Jan Friesse <jfriesse@redhat.com>
Reviewed-by: Christine Caulfield <ccaulfie@redhat.com>
totemudpu: Send msgs to all members occasionally

To follow spec it's needed to send messages to all nodes (not only
active members) from time to time to detect merge.

This is needed in situations when totemsrp merge timer isn't running
(because there is enough messages sent by processors) to detect merge.

Example scenario:
- 3 nodes, all of them running cpgverify
- One node is isolated (iptables for example)
- Node is un-isolated

Without this commit, node will not merge as long as the cpgverify is
running.

Signed-off-by: Jan Friesse <jfriesse@redhat.com>
Reviewed-by: Christine Caulfield <ccaulfie@redhat.com>