A migratable server could fail to come up on every possible
configured machine. This attribute controls how many further
attempts, after the first one, should be tried.
Note that each attempt specified here indicates another full
circut of migrations amongst all the configured machines. So for
a 3-server cluster, and the default value of 3, a total of 9
migrations will be attempted.
If it is set to -1, migrations will go on forever until the
server starts.
(Interface=weblogic.management.configuration.ClusterMBean Attribute=getAdditionalAutoMigrationAttempts)