Configure Elasticsearch for safe full restart

Elasticsearch uses three configuration variable to safely and efficiently
handle a full cluster restart.  One configures the expected number of
servers, another the minimum acceptable number of servers, and another
the amount of time after the minimim acceptable number of servers have
joined to wait for the expected number of servers.

Note also that the required minimum number of master nodes must also have
joined before the cluster can start.

Change-Id: Id4bb3e54706740fb8c7c0d0e91b477d2fc5a7672