[SPARK-5006][Deploy]spark.port.maxRetries doesn't work

https://issues.apache.org/jira/browse/SPARK-5006

I think the issue is produced in https://github.com/apache/spark/pull/1777. 

Not digging mesos's backend yet. Maybe should add same logic either.
You could use `conf.getOption(...).foreach { portRetriesConf => [...] }` but I'm not sure that it's a huge win.