wsrep_notify_cmd does not get enough information

[shinguz]

This is a feature request:

We cannot distinguish on the Donor node in the script if SST is read-only (mysqldump, rsync) or read-write (xtrabackup). Thus we cannot take appropriate actions (starting FW rules).

rsync

--status Synced --uuid 61c9d32a-f6c9-11e3-b08a-bf520bcbb4d7 --primary yes --index 0 --members
--status Donor
--status Synced

xtrabckup

--status Synced --uuid 61c9d32a-f6c9-11e3-b08a-bf520bcbb4d7 --primary yes --index 0 --members
--status Donor
--status Synced

Would be nice if --status (or similar) would have a different value. For example:

Donor/Synced
Donor/Desynced

So we can take (or skip) the appropriate actions.