Sync all config files across all nodes when adding new node (bnc#867048)

Previously we used `csync2 -xv -P $(hostname)` to sync files only to the
new node.  Unfortunately this leaves all other files marked dirty on
that node, so a subsequent join of another node may have a failed csync2
run, causing e.g.: corosync.conf to be out of date at that point on one
node.  To fix this, we just sync all files across the cluster when doing
a join.  *sigh*

Signed-off-by: Tim Serong <tserong@suse.com>
Use `csync2 -R` to cleanup DB when removing node (bnc#867039)

Signed-off-by: Tim Serong <tserong@suse.com>
Ensure corosync and SBD config are marked dirty before syncing

Signed-off-by: Tim Serong <tserong@suse.com>
Set/clear two_node in corosync.conf (bnc#866435)

Signed-off-by: Tim Serong <tserong@suse.com>
Warn if /dev/watchdog not present

Signed-off-by: Tim Serong <tserong@suse.com>