[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.
We should initialize this val until it is used but not from the beginning of initialization of Utils class. Define `portMaxRetries` as a function could solve this issue either.