Turn off health checking success logging

By default xinetd logs each time a service is run when it's successful
or not.  This leads to two lines of log spam every time the health check
is run.
Fixed indentation in galera::status
Support setting available_when_read_only.

When available_when_readonly is set to 0, the clustercheck script will
return 503 Service Unavailable if the node is in read-only mode.
Merge pull request #17 from twc-openstack/master

Turn off health checking success logging
Merge "Support setting available_when_read_only."