Remove RMI gcInterval system props from default Java VM options

In Java 6 the default value for those props changed to 3600000 and AS7 requires Java 6 or later. Those props are just redundant.

> -Dsun.rmi.dgc.client.gcInterval=3600000 -Dsun.rmi.dgc.server.gcInterval=3600000

http://docs.oracle.com/javase/6/docs/technotes/guides/rmi/sunrmiproperties.html